Multi Tech Systems Network Card MT2834ZPX User Manual

Model Number MT2834ZPX  
Owner's Manual  
 
Contents  
Chapter 1 - Introduction and Description  
Introduction................................................................................................................ 5  
Modem Features ....................................................................................................... 5  
Fax Features ............................................................................................................. 6  
Product Description................................................................................................... 6  
How to Use This Manual........................................................................................... 7  
Chapter 2 - Installation and Configuration  
Installation ................................................................................................................. 9  
Safety Warnings ........................................................................................................ 9  
Configuration/Installation Procedure ...................................................................... 10  
Is Your MT2834ZPX Ready for Use? ..................................................................... 12  
Operating Your MT2834ZPX .................................................................................. 13  
Simple Operations .................................................................................................. 14  
Chapter 3 - Software Configuration  
Introduction.............................................................................................................. 15  
ConfiguringSoftware for Your Modem ............................................................ 15  
PC Initialization Strings........................................................................................... 16  
Changing Default Parameters ................................................................................ 17  
Configuring Software for Your Computer ............................................................... 17  
Configuring Software for the Remote System ............................................... 18  
Terminal Emulation ......................................................................................... 18  
File Transfer Protocols.................................................................................... 19  
When to Disable Data Compression ...................................................................... 19  
Disabling Error Correction .............................................................................. 20  
The 16550 UART and Windows 3.1 ....................................................................... 20  
Chapter 4 - AT Commands, S-Registers and Result Codes  
Dialing/On-Line/Answering ..................................................................................... 22  
Modem AT Commands ........................................................................................... 23  
Remote Configuration..................................................................................... 38  
Remote Configuration Procedures ................................................................. 38  
Password Commands.................................................................................... 39  
S-Registers .............................................................................................................. 40  
AT Commands and S-Register Summary ...................................................... 48  
 
Chapter 5 - Troubleshooting  
Troubleshooting....................................................................................................... 49  
The Modem Does Not Respond to Commands ............................................ 49  
The Modem Dials But Cannot Make a Connection ....................................... 51  
The Modem Disconnects While Online.......................................................... 53  
The Modem Cannot Connect When Answering ............................................ 54  
File Transfer Is Slower Than It Should Be ..................................................... 54  
Losing Data ..................................................................................................... 54  
Getting Garbage Characters on the Monitor ................................................. 55  
Fax and Communications Software Won’t Run at the Same Time .............. 55  
Chapter 6 - Testing Your Modem  
Local Analog Loopback Test/V.54 Loop 3 .............................................................. 56  
Digital Loopback Test/V.54 Loop 2 (Local/Manual) ............................................... 57  
Digital Loopback Test/V.54 Loop 2 (Remote/Automatic) ....................................... 58  
Chapter 7 - Service, Warranty and Tech Support  
Introduction.............................................................................................................. 60  
Limited Warranty ..................................................................................................... 60  
On-line Warranty Registration ........................................................................ 61  
Tech Support ........................................................................................................... 61  
Recording Modem Information ....................................................................... 61  
Service ..................................................................................................................... 62  
About the Multi-Tech BBS....................................................................................... 63  
To log on to the Multi-Tech BBS ..................................................................... 63  
To Download a file .......................................................................................... 63  
About CompuServe/Internet ................................................................................... 65  
About the Multi-Tech Fax-Back Service ................................................................. 65  
Appendix A - Technical Specifications  
Appendix B - Tone Dial Frequencies  
Appendix C - FCC and Canadian Regulations  
FCC Regulations for Telephone Line Interconnection........................................... 71  
Canadian Limitations Notice ................................................................................... 74  
Index  
 
Chapter 1 - Introduction and Description  
Chapter 1 - Introduction and Description  
Introduction  
Welcome to the world of data communications. You have acquired  
one of the finest intelligent data and fax modems available today,  
model MT2834ZPX, from Multi-Tech Systems. This Owner’s Manual  
will help you install, configure, test and use your MT2834ZPX data/fax  
modem.  
Modem Features  
Your MT2834ZPX modem meets the proposed Enhanced V.34 ITU  
standard for data signalling rates as high as 33.6/31.2K bps full-duplex  
mode. Connections are made on Public Switched Telephone Networks  
(PSTNs). V.34 supports and is compatible with all V.32/V.32bis/  
V32terbo features including EIA extended Automode, adaptive line  
probing, automatic symbol rate and carrier frequency during start-up,  
and retrain and rate renegotiation (in 2400 bps increments).  
Your modem features CCITT V.42 error correction and V.42bis data  
compression, providing 100% error-free data transmission. V.42 error  
correction incorporates MNP( Classes 3 and 4, and LAP-M. You may  
select V.42bis data compression for 4-1 throughput, or MNP Class 5  
for 2-1 throughput.)  
Your MT2834ZPX offers interactive automatic dialing, as well as  
Command Mode option configuration. You may store up to ten  
command line/telephone numbers, of up to 60 characters each, in the  
modem’s nonvolatile memory. The modem pulse or tone dials, and  
recognizes dial tones and busy signals for reliable call-progress  
detection. The modem can detect AT&T calling card tones. It is FCC-  
Registered for connection to telephone networks without any Data  
Access Arrangements (DAA’s).  
Your modem also features Remote Configuration which permits you to  
assist users at remote sites, saving you the time and trouble of site  
visits and preventing misinterpretation of configuration instructions.  
 
5
MT2834ZPX Owner's Manual  
Fax Features  
Your MT2834ZPX meets the CCITT V.17 standard for sending and  
receiving faxes. When linked to a compatible fax machine or modem,  
it can transmit faxes at 14.4 K bps. It also meets the CCITT’s Group 3  
Designation for sending and receiving faxes at 9600 bps; and Group 2  
Designation for sending and receiving faxes at 4800 bps. The  
MT2834ZPX is also downward-compatible with modems to speeds as  
low as 300 bps, so it can send and receive faxes with any fax machine  
in the world.  
Product Description  
The MT2834ZPX is a internal half-length fax/modem card for IBM  
Personal Computers (PC, XT, AT Pentium or compatible units); and  
fits into a full- or half-size expansion slot. The MT2834ZPX provides  
dial-up asynchronous communication capability with other personal  
computers, terminals, on-line computer services or other types of  
computer systems. Connection to the phone line is made possible by  
an RJ11 modular type connector. The MT2834ZPX can be configured  
as either a COM1, COM2, COM3, or COM4 communication port; with  
a selection of 5 IRQ values. Selection of a specific COM port/IRQ  
value is accomplished by choosing the proper berg jumpers located on  
the MT2834ZPX's circuit board. Hardware configuration and  
installation procedures are described in Chapter 2.  
6
 
Chapter 1 - Introduction and Description  
How to Use This Manual  
This manual is divided into seven chapters and two appendices. The  
information contained in each chapter and appendix is as follows:  
Chapter 1 - Introduction and Description  
Chapter 1 begins with a short product introduction and description;  
followed by a guide (which you are now reading) to the use of this  
manual.  
Chapter 2 - Installation and Connection  
Chapter 2 documents the procedure for connecting the MT2834ZPX to  
your computer and to the phone line. Details are given, supported by  
illustrations on determining Base I/O addressing and setting IRQ  
values as a guide for installing your MT2834ZPX to the point of  
operation.  
Chapter 3 - Software Configuration  
Chapter 3 documents communication software configuration  
recommended specifically for the MT2834ZPX. There is also some  
discussion of how to identify the limitations and capabilities of your  
computer before the software installation process is done. Some other  
issues covered in this chapter include setting up initialization strings,  
changing default parameters, configuring software for the remote  
system and file transfer protocols.  
Chapter 4 - "AT" Commands and S-Registers  
This chapter focuses on the use of “AT” commands and S-Registers.  
Chapter 4 provides basic steps for originating and answering calls and  
a summary of commands that enable the user to establish, read, and  
modify parameters in addition to dialing.  
Chapter 5 - Troubleshooting Your MT2834ZPX  
Chapter 5 lists some basic and specific actions to take if your  
MT2834ZPX is not operational.  
 
7
MT2834ZPX Owner's Manual  
Chapter 6 - Testing Your Modem  
Chapter 6 covers the modem's built-in test features. These are:  
Power-on Self Test, Local Analog Loopback, Digital Loopback and  
Remote Digital Loopback Tests. We have included a description of  
each test and how to use each test procedure.  
Chapter 7 - Service, Warranty & Technical  
Support/ BBS  
Chapter 7 provides instructions for getting modems serviced at the  
factory and information on product warranty; information about Multi-  
Tech's user Bulletin Board Service (BBS) and receiving technical  
support via the CompuServe and Internet forums.  
Appendices  
Appendix A - Technical Specifications  
Appendix B - Tone Dial Frequencies  
Appendix C - FCC and Canadian Regulations  
8
 
Chapter 2 - Installation and Configuration  
Chapter 2 - Installation and Configuration  
Installation  
This chapter provides you with the procedures to install the Multi-Tech  
MT2834ZPX card in your ISA or EISA bus personal computer.  
Hardware installation involves:  
1) Opening your PC.  
2) Setting card configuration (determining COM port  
setting and IRQ level).  
3) Installing the card into the PC.  
Safety Warnings  
1. Never install telephone wiring during a lightning storm.  
2. Never install telephone jacks in wet locations unless the jack is  
specifically designed for wet locations.  
3. This product is to be used with UL and CUL listed computers.  
4. Never touch uninsulated telephone wires or terminals unless the  
telephone line has been disconnected at the network interface.  
5. Use caution when installing or modifying telephone lines.  
6. Avoid using a telephone (other than a cordless type) during an  
electrical storm. There may be a remote risk of electrical shock  
from lightning.  
7. Do not use the telephone to report a gas leak in the vicinity of the  
leak.  
 
9
MT2834ZPX Owner's Manual  
Configuration/Installation Procedure  
Perform the procedures in Table 2-1 to configure and install the  
MT2834ZPX card into your ISA or EISA bus host computer.  
Table 2-1. Configuration and Installation Procedure  
Step  
Procedure  
1
Make sure your computer and any peripheral equipment  
connected to it, are turned off. Failure to do so may damage both  
your modem and your PC. The card may be installed in any 286-,  
386- , 486- or Pentium based computer with an ISA or EISA bus  
architecture.  
2
Remove the cover of your computer as instructed in your  
computer’s documentation.  
3
4
Locate the unused slot(s) which you will be using for your modem  
card, and remove the slot cover(s) per the instructions in your  
computer’s documentation.  
Figure 2-1 illustrates the default COM port and IRQ value setting  
for this card (COM2/IRQ3). If your application requires an  
alternate setting, remove the berg jumpers from the COM2/IRQ3  
position and place them in a position that supports your  
application. The MT2834ZPX can be configured for either a  
COM1, COM2, COM3 or COM4 communication port; with a  
selection of five IRQ values for each port. By this means, the user  
may select an identical COM port because of the expanded IRQ  
value selection option (e.g., the MT2834ZPX has a factory default  
of COM2/IRQ3...a Mouse device can also be configured at COM2  
but at IRQ4...a Printer device configured at COM2 but at IRQ7...).  
10  
 
Chapter 2 - Installation and Configuration  
Figure 2-1. MT2834ZPX Printed Circuit Board and Alternate COM  
Port/IRQ Settings  
 
11  
MT2834ZPX Owner's Manual  
Table 2-1 (Cont'd). Configuration and Installation Procedure  
Step Procedure  
5
Install the MT2834ZPX card into the selected expansion slot(s) in  
the same manner as any other add-on card, as instructed in your  
computer’s documentation.  
6
7
Fasten the retaining bracket to the computer chassis and replace  
the cover.  
Your MT2834ZPX requires a modular LINE JACK. This is typically  
an RJ11C or RJ11W jack, but could also be an RJ12 or RJ13  
jack. To connect the modem to the PSTN line, plug one end of  
the RJ11 cable that is provided with the modem into the LINE  
JACK connector and the other end into the phone-company-  
provided RJ11C or RJ11W modular phone jack.  
If you wish to have a telephone set connected to the same  
telephone line for voice communications, you may plug a  
telephone set into the modem's connector labeled PHONE JACK.  
This connector is provided as a convenience. Simply plug one  
end of the RJ11C's modular jack that is provided with the modem  
into the modem's PHONE JACK connector and the other end into  
the telephone's RJ11C's connector. Note: Any cables connected  
to the computer must be shielded to reduce interference.  
8
Turn power on to your computer.  
Is Your MT2834ZPX Ready for Use?  
As soon as you connected power to the modem, if you’re an  
experienced modem user, you may simply want to check your  
modem’s settings for data compression, error correction, and so on.  
You may find that you can get moving quite quickly if you just issue an  
ATL5, ATL6 and an ATL7 command. These commands lists how  
your modem is currently configured. If you come across a setting  
you’re unsure of, refer to Chapters 3 and 4 of this manual for AT  
command and S-Register explanations and defaults.  
If you’re a novice, please continue to the next sections of this chapter.  
12  
 
Chapter 2 - Installation and Configuration  
Operating Your MT2834ZPX  
You control your MT2834ZPX by issuing AT commands and setting S-  
Registers. Right now your MT2834ZPX is set up for the most typical  
user application, that is, as a traditional modem set to make a dial-up  
call to a remote installation where the call is answered automatically;  
therefore, you shouldn’t need to change the current default  
configuration. (If however, you know that your application does not  
follow this profile, please refer to Chapters 3 and 4 for AT Commands  
and S-Registers.)  
In operating your MT2834ZPX it is likely that you will use your data  
communications software to either:  
enter “terminal” mode, where you can “speak most directly” to the  
modem by issuing AT commands, or to  
launch a datacomm session through a set of modem  
configurations which you select and then associate with a target  
telephone number. Once you have created, saved, and named  
this set of information according to your connection needs and  
your datacomm software’s conventions, the software then  
simplifies your dialing because you needn’t reconfigure your  
modem, nor run the risk of mistakenly keying-in incorrect  
information.  
Either way, you need to understand that an AT command is the  
method by which your modem is controlled, and must therefore prefix  
nearly all commands. AT stands for attention, and alerts the modem  
that a command follows. You may enter these commands with either  
upper- or lower-case characters. Entering AT automatically sets the  
modem’s serial baud rate to match your computer’s and also sets the  
modem’s parity. It also clears the modem’s command buffer.  
Once you’re in terminal mode, enter AT followed by <CR> to check  
whether your modem is operational. If everything’s fine, your modem  
will respond OK.  
 
13  
MT2834ZPX Owner's Manual  
Simple Operations  
You can dial a number by using the ATD command and the phone  
number of the modem with which you wish to connect, e.g.,  
ATD6127853500. Your modem will dial the number; a “scrambling”  
noise is heard as the modem negotiates the kind of connection it can  
make, and once the modems have settled on a common connection, a  
connect message on your computer’s video is displayed.  
To hang up a call, enter +++ATH<CR>. Your modem will return on  
hook, just as if you had returned a phone’s handset to its cradle. Your  
video now displays OK, signifying that your modem is ready for your  
next command.  
14  
 
Chapter 3 - Software Configuration  
Chapter 3 - Software Configuration  
Introduction  
Communications software must be configured to work with your  
modem, your computer, and the remote system it is calling.  
Fortunately, most communications programs make the process easy  
by providing a default initialization string for your modem as well as  
defaults for most of the other required parameters.  
Configuring Software for Your Modem  
Because remote computers may have different connection  
requirements such as speed, number of bits, parity, log-on sequences,  
etc., communications software is typically configured by sessions,  
each session having a unique configuration for a given connection  
(e.g., to a BBS or commercial on-line service). Most communications  
programs, however, have a separate modem configuration menu  
because modem configurations rarely change from session to session.  
The most important configuration is the modem initialization string.  
This is a sequence of commands the software uses to configure the  
modem when the communications software is loaded or when a  
session begins. Always begin the initialization string with the ATtention  
command AT, then follow it with the modem reset command, &F.  
Issuing a reset command before other commands ensures that you  
are starting with a known state.  
The rest of the commands in the initialization string depend on the  
capabilities of the modem and what you want it to do. Some older  
communications programs require you to create the initialization string  
by yourself. Most modern communications programs, however, provide  
you with a ready-made initialization string that is automatically  
selected when you choose your modem model from a list. It is a poor  
idea to use an initialization string intended for another modem,  
especially one from another manufacturer, because modem  
capabilities and command implementations vary from modem to  
modem. However, if your MT2834ZPX does not appear on a modem  
list, you may use the MultiModemII initialization string.  
 
15  
MT2834ZPX Owner's Manual  
PC Initialization Strings  
We recommend the following initialization string for a MT2834ZPX  
connected to a PC-compatible computer:  
AT &F X4 S0= 2 ^M  
This string resets the MT2834ZPX to the factory default settings,  
selects extended result codes with NO DIAL TONE and BUSY, and  
turns on auto-answer to answer on the second ring. ^M must end  
every string sent to the modem from software. It is the ASCII code for  
the RETURN key on most keyboards, and the default code for the  
carriage return character in the MT2834ZPX and most  
communications programs. The carriage return character is defined in  
the MT2834ZPX in S-register S3; if you change it, you must also  
change the carriage return character code used in your  
communications software. If you send a command directly to the  
modem in terminal mode rather than indirectly through  
communications software, you must end the command string by  
pressing the RETURN key (<CR>) instead of adding ^M to the string.  
Figure 3-1. The MEW Modem Initialization Setup  
*Note that the above and following setup screens are examples found in  
MultiExpress for Windows (MEW), and that other 3rd party data communication  
software is similar but different.  
16  
 
Chapter 3 - Software Configuration  
Changing Default Parameters  
The default values for the other parameters in modem configuration  
menus rarely need changing. They typically include the dialing prefix  
(ATDT for touch-tone service and ATDP for rotary service), the dialing  
suffix (^M), the hang-up string (+++ATH0^M), and response  
messages (RING, NO CARRIER, BUSY, etc.). Communications  
software with a host mode might also include an auto-answer string  
(AT S0=1^M).  
Configuring Software for Your Computer  
You must configure your communications software to match your  
computer’s configuration. If the MT2834ZPX is connected to the  
COM2 communications port, you must tell the software you are using  
COM2. Another important parameter is the serial port baud rate. This  
is the speed at which your modem communicates with your computer,  
not the speed at which your modem communicates with another  
modem. When V.42bis data compression is enabled, you must have a  
serial port baud rate four times the transmission speed of the modem  
to optimize making data compression effective.  
Figure 3-2. MEW Configuration Parameters Screen  
 
17  
MT2834ZPX Owner's Manual  
Configuring Software for the Remote System  
You must meet the requirements of the remote system for successful  
communications. Though the MT2834ZPX can automatically match  
the speed of the other modem, you must specify parameters such as  
type of flow control, break length, number of data bits, number of stop  
bits, and parity. If you set these parameters incorrectly with the remote  
system, gibberish will appear on your screen (See Figure 3-2).  
Terminal Emulation  
If you are accessing the remote computer as if from an on-site  
terminal, the keyboard codes used by your computer may not match  
the ones used by the remote computer. To be compatible with the  
remote computer, your software must be able to substitute the  
appropriate codes in what is known as terminal emulation. Most  
communications programs can emulate the most common mainframe  
terminals, including the DEC VT100, VT102, and VT52 terminals, and  
the basic TTY mode. If in doubt about which to choose for a BBS, try  
ANSI or VT100 first. The following is the MultiExpress for Windows  
Terminal Emulation selection screen:  
Figure 3-3. MEW Terminal Emulation Setup Screen  
18  
 
Chapter 3 - Software Configuration  
File Transfer Protocols  
When you upload or download files with your modem, the host  
computer will ask which file transfer protocol you want to use. Most  
communications programs allow you to choose a default protocol.  
Your software’s documentation should list the ones it can use (not all  
communications programs support all protocols). Zmodem is the  
default protocol in MultiExpress for Windows, and we recommend it for  
most transfers. The following is the MEW File Transfer Protocols  
screen:  
Figure 3-4. MEW File Transfer Protocols Screen  
When to Disable Data Compression  
The speed advantage hardware compression gives you is entirely  
dependent on how much the data being transmitted can be  
compressed. If the data is already in compressed form—a .ZIP or a  
.SIT file, for example—trying to compress it more will actually slow the  
transmission slightly compared to transmitting the same file with  
compression disabled. This effect will be most noticeable if your  
modem negotiates MNP 5 compression with the other modem. V.42bis  
will not try to further compress a compressed file, but MNP 5 will.  
The command to disable compression is AT &E14 <CR>. If you use  
your modem mostly for downloading long, compressed files from  
BBSs, you may want to include the &E14 command in your  
initialization string as follows:  
AT &F S0=0 X4 &E14 ^M  
 
19  
MT2834ZPX Owner's Manual  
As a general rule, you should try to transmit files in already-  
compressed form rather than relying on V.42bis hardware  
compression. Because software compression is more efficient than  
hardware compression, you will have a higher throughput with the  
former. Of course, this efficiency does not include the time spent  
compressing and decompressing .ZIP or .SIT files, but it will save on  
phone bills. And hardware compression will still be there for those  
occasions when it is inconvenient to compress a file with software.  
Disabling Error Correction  
By default, the MT2834ZPX is set to auto-reliable mode. In this mode  
the MT2834ZPX determines during the handshake whether the other  
modem is using V.42 error correction. If it is, the MT2834ZPX then  
switches itself to reliable mode and enables error correction. If it is not,  
the MT2834ZPX remains in non-error correction mode.  
Typically, we recommend that you leave the MT2834ZPX set to auto-  
reliable mode (&E1). However, you may encounter some  
circumstances in which the MT2834ZPX will work better with error  
correction turned off. For example, it has been reported that on  
CompuServe error correction will slow file transfers at modem speeds  
of 9600 bps and under. If this is a problem for you, you can turn off  
error correction with the command AT &E0, or you can include the  
command in your initialization string as follows:  
AT &F S0=0 X4 &E0 ^M  
The 16550 UART and Windows 3.1  
Windows 3.1 may cause a loss of data when communicating at high  
speed, even with a 16550 UART installed. Because Windows is  
multitasking—it switches between several programs running at the  
same time—it can make the serial port wait briefly while Windows  
performs other tasks. Meanwhile, incoming data can be lost. The older  
8250A and 16450 UARTs can store data in a one-byte first in-first out  
(FIFO) buffer (a memory area in the UART in which the first bit in is  
the first out), but once the buffer is full, the data is lost. The 16550 has  
a 16-byte FIFO buffer, which accounts for much of its high speed.  
However, in Windows 3.1, the 16550’s FIFO buffer is disabled by  
default.  
20  
 
Chapter 3 - Software Configuration  
To enable the buffer, use Notepad to open the SYSTEM.INI file in your  
Windows directory, and add the following line to the [386Enh] section:  
COMnFIFO=1  
where n is the number of the COM port the 16550 is installed on. For  
example, if the 16550 is installed on COM2, the line should be:  
COM2FIFO=1  
After you save SYSTEM.INI you must restart Windows for the change  
to take effect.  
However, there is another problem when the FIFO buffer is enabled:  
Windows cannot recognize the COM port because of a bug in the  
Windows 3.1 serial port driver, COMM.DRV. The only way around this  
problem is to replace the COMM.DRV file in the WINDOWS\SYSTEM  
directory with another driver. Several drivers are available  
commercially or on BBSs that will solve this problem. A freeware driver  
called CyberCom is available as CYBERC.ZIP on CompuServe in the  
IBM Communications Forum, Library 0. CyberCom will enable  
Windows communications at speeds up to 115,200 bps if you have a  
16550 UART installed.  
 
21  
MT2834ZPX Owner's Manual  
Chapter 4 - AT Commands, S-Registers and Result  
Codes  
Dialing/On-Line/Answering  
There are several basic steps for “originating” and “answering” in data  
communication mode:  
1. Load communication software  
2. Dial  
3. Establish On-Line connection  
4. Terminate Call  
A simple way to dial is from the keyboard of your computer or terminal.  
You enter a command on the keyboard to tell the MT2834ZPX to dial.  
If you use a sophisticated communications software package  
(e.g., MultiExpress for Windows), the software tells you to enter phone  
numbers and other information. If this is the case, the software, and  
not you, gives the dialing commands to the modem. All of the  
commands, S-Registers and intelligent features of the MT2834ZPX is  
taken care of by the software.  
If you are giving commands directly to your modem (and not through  
your software), each command must begin with AT (ATtention  
Characters). AT characters may be entered in upper or lower case.  
Entering AT automatically sets the modem’s speed to match the speed  
of the computer or terminal, and also sets the modem’s parity. If you  
are using a terminal, you can issue commands directly, but computers  
must be placed in terminal mode before the modem recognizes  
commands. To operate the computer in terminal mode, you must run  
a data comm package like MultiExpress, or MultiExpress for Windows,  
depending on the type of datacomm call you want to place and  
whether you are calling under a DOS or Windows environment. Refer  
to your software's documentation to load and run the datacomm  
software.  
AT characters alert the modem that a command follows. The AT  
Command can also be used to clear the command buffer, by simply  
typing AT and hitting RETURN.  
The letter D in a command causes the modem to dial the numbers  
immediately following it (e.g., ATD6127853500).  
22  
 
Chapter 4 - AT Commands, S-Registers and Result Codes  
The MT2834ZPX responds with “CONNECT” on your video display  
after the number is dialed and a connection signal is detected (since  
the MT2834ZPX defaults to Enhanced V.34/V.42/V.42bis, the actual  
response is "CONNECT LAPM COMPRESSED”). The modem is now  
in “On-Line” mode, and is ready to communicate with a host site.  
If no connection signal is detected within 45 seconds (this time period  
can be adjusted by S-Register S7), the MT2834ZPX goes On Hook/  
hangs up and returns to Command mode. At this point, your video  
displays “NO CARRIER”.  
Enter +++ATH<CR> to Hang Up On-Line (bring modem on-hook), and  
terminate the modem's On-Line mode. At this point, your video  
displays “OK”.  
In addition to the call originating capabilities, the MT2834ZPX can also  
automatically answer incoming calls. You need not be present. You  
can, however, control the situation by configuring the modem to either  
answer or not to answer, or to answer after a specified number of  
rings. This is done by setting the value of S-Register S0 (modem  
defaults to automatically answer an incoming call after one ring).  
Modem AT Commands  
AT commands are the means by which you, and your communications  
software, are able to communicate with and configure your modem.  
They enable you to establish, read, and modify parameters in addition  
to dialing. The following provides a summary and brief explanation of  
the AT commands recognized by the MT2834ZPX.  
COMMAND:  
VALUES:  
DEFAULT:  
AT  
n/a  
n/a  
DESCRIPTION:  
Attention Code that precedes most command  
strings except A/, A: and Escape Codes.  
COMMAND:  
VALUES:  
Return  
n/a  
DEFAULT:  
n/a  
DESCRIPTION:  
Pressing RETURN key executes most commands.  
 
23  
MT2834ZPX Owner's Manual  
COMMAND:  
VALUES:  
DEFAULT:  
A
n/a  
n/a  
DESCRIPTION:  
Answer call, even if no ring present.  
COMMAND:  
VALUES:  
DEFAULT:  
A/  
n/a  
n/a  
DESCRIPTION:  
Repeat last command. (Do not precede this  
command with AT. Do not hit RETURN to  
execute.)  
COMMAND:  
VALUES:  
DEFAULT:  
A:  
n/a  
n/a  
DESCRIPTION:  
Continuous redial (10 redials in DOC units) of  
last number until answered.  
(Not used in International Models.)  
COMMAND:  
VALUES:  
DEFAULT:  
$
n/a  
n/a  
DESCRIPTION:  
This symbol placed in dialing string enables  
the modem to detect AT&T's "call card"  
tones to access user's calling card when  
originating an on-line connection--  
COMMAND:  
VALUES:  
DEFAULT:  
$An  
n = 0 or 1  
$A0  
DESCRIPTION:  
$A0 discards data during auto-reliable time  
period.  
$A1 buffers data during auto-reliable time  
period.  
24  
 
Chapter 4 - AT Commands, S-Registers and Result Codes  
COMMAND:  
VALUES:  
DEFAULT:  
#An  
n = 0 thru 3  
#A0  
DESCRIPTION:  
#A0 selects initial handshake at 33,600 to 31,200 to 28,800  
to 24000 to 21,600 to 19,200 to 16,800 to 14,400 to12,000  
to9600 to 4800 to 2400 to 1200 to 300 bps.  
#A1 selects initial handshake at 33,600 bps only.  
#A2 selects initial handshake at 33,600 to 31,200 to 28,800  
to 24000 to 21600 to 19,200 to 16,800 19,200 to 14,400  
to 9600 to 4800 bps.  
#A3 selects initial handshake at 2400 to 1200 to 300 bps.  
COMMAND:  
VALUES:  
DEFAULT:  
&Bn  
n = 0 or 1  
&B0  
DESCRIPTION:  
&B0 selects normal transmit buffer size.  
&B1 selects reduced transmit buffer size.  
COMMAND:  
VALUES:  
DEFAULT:  
&BSn  
n = 0 or 1  
&BS1  
DESCRIPTION:  
&BS0 selects maximum transmit block size of 64 characters.  
&BS1 selects maximum transmit block size of 256  
characters (MNP mode)/128 characters (LAP-M mode).  
COMMAND:  
VALUES:  
DEFAULT:  
Bn  
n = 0 or 1  
B0  
DESCRIPTION:  
B0 selects V.21 for 300 bps operation.  
B1 selects for 300 bps operation.  
(Not used in International Models.)  
COMMAND:  
VALUES:  
DEFAULT:  
$BAn  
n = 0 or 1  
$BA0  
DESCRIPTION:  
$BA0 selects speed conversion on.  
$BA1 selects speed conversion off.  
 
25  
MT2834ZPX Owner's Manual  
COMMAND:  
VALUES:  
DEFAULT:  
&Cn  
n = 0, 1, 2 or 4  
&C1  
DESCRIPTION:  
&C0 forces Carrier Detect on.  
&C1 lets Carrier Detect act normally.  
&C2 lets Carrier Detect drop S24 time on disconnect.  
&C4 resets modem when Carrier Detect drops.  
COMMAND:  
VALUES:  
DEFAULT:  
&CDn  
n = 0 or 1  
&CD0  
DESCRIPTION:  
&CD0 execute cleardown on disconnect.  
&CD1 do not execute cleardown on disconnect.  
COMMAND:  
VALUES:  
DEFAULT:  
Ds  
s = phone #  
n/a  
DESCRIPTION:  
Dial a telephone number “s”, where s may  
include up to 60 digits or T, P, R, comma and ; characters.  
COMMAND:  
VALUES:  
DEFAULT:  
DsNd  
s = phone # and d = 0 thru 9  
n/a  
DESCRIPTION:  
Store telephone number. To store, phone number ”s“ is en  
entered and followed by N and then Directory Number “d.”  
COMMAND:  
VALUES:  
DEFAULT:  
&Dn  
n = 0 thru 3  
&D2  
DESCRIPTION:  
&D0 means DTR is ignored  
&D1means modem returns to command mode.  
&D2 lets modem react to DTR normally.  
&D3 causes modem to reset to modem default parameters.  
COMMAND:  
VALUES:  
DEFAULT:  
$Dn  
n = 0 or 1  
$D0  
DESCRIPTION:  
$D0 disables DTR Dialing.  
$D1 enables DTR Dialing.  
26  
 
Chapter 4 - AT Commands, S-Registers and Result Codes  
COMMAND:  
VALUES:  
DEFAULT:  
%DFn  
n = 0 or 1  
%DF0  
DESCRIPTION:  
%DF0 selects V.34 Line Probe Data in Graph Format.  
%DF1 selects V.34 Line Probe Data in Table Format.  
COMMAND:  
VALUES:  
DEFAULT:  
%DPn  
n = 0 or 1  
%DP0  
DESCRIPTION:  
%DP0 selects not to read Line Probe Information from  
DSP during handshaking.  
%DP1 selects read Line Probe Information  
from DSP during handshaking.  
COMMAND:  
VALUES:  
DEFAULT:  
>DTn  
n = 0 or 1  
>DT0  
DESCRIPTION:  
>DT0 disables modem detecting DTMF tones.  
>DT1 enables modem detecting and reporting DTMF tones  
when it is off-hook.  
COMMAND:  
VALUES:  
DEFAULT:  
En  
n = 0 or 1  
E1  
DESCRIPTION:  
E0 selects do not echo Command mode characters.  
E1 selects echo Command mode characters.  
COMMAND:  
VALUES:  
DEFAULT:  
$EBn  
n = 0 or 1  
$EB0  
DESCRIPTION:  
$EB0 selects 10 bit mode.  
$EB1 selects 11 bit mode.  
COMMAND:  
VALUES:  
&En  
n = 0 thru 15  
DEFAULT:  
&E1, &E4, &E6, &E10, &E13, &E15  
DESCRIPTION:  
&E0 selects no error correction.  
&E1 selects V.42 Auto-reliable Mode.  
&E2 selects V.42 Reliable Mode.  
 
27  
MT2834ZPX Owner's Manual  
COMMAND:  
&En (Cont'd)  
&E3 selects no modem-initiated flow control.  
&E4 selects CTS modem-initiated flow control.  
&E5 selects Xon/Xoff modem-initiated flow control.  
&E6 selects Xon/Xoff not passed through.  
&E7 selects Xon/Xoff passed through.  
&E8 selects Enq/Ack pacing off.  
&E9 selects Enq/Ack pacing on.  
&E10 selects Normal Mode flow control off.  
&E11 selects Normal Mode flow control on.  
&E12 selects Pacing off.  
&E13 means Pacing on.  
&E14 means data compression disabled.  
&E15 means data compression enabled.  
COMMAND:  
VALUES:  
DEFAULT:  
%En  
n=0 thru 5  
%E1  
DESCRIPTION:  
%E0 = Modem Won’t Escape.  
%E1 = +++ Method (default setting).  
%E2 = Break Method.  
%E3 = Either +++ or Break Method.  
%E4 = No "OK" Response to +++  
%E5 = "OK" Response to +++  
COMMAND:  
VALUES:  
DEFAULT:  
#Fn  
n = 0 thru 2  
#F2  
DESCRIPTION:  
#F0 means no fallback when on-line.  
#F1 means fallback from 33600 to 4800 bps  
when on-line (increments of 2400 bps).  
#F2 means fallback to 4800 bps from 33.6K  
bps/fall forward if line improves (increments  
of 2400 bps).  
COMMAND:  
VALUES:  
DEFAULT:  
&Fn  
n = 0, 8 or 9  
&F8  
DESCRIPTION:  
&F loads factory default values from ROM.  
&F8 reads factory default values when &F is issued.  
&F9 reads parameters stored in nonvolatile  
memory when &F is issued.  
28  
 
Chapter 4 - AT Commands, S-Registers and Result Codes  
COMMAND:  
VALUES:  
DEFAULT:  
$Fn  
n = 0 or 1  
$F1  
DESCRIPTION:  
$F0 selects do not fall back to normal  
connect if CR received.  
$F1 selects fall back to normal connect if CR received.  
COMMAND:  
VALUES:  
DEFAULT:  
&Gn  
n = 0, 1 or 2  
&G0  
DESCRIPTION:  
&G0 turns off CCITT guard tones.  
&G1 turns on CCITT 550 Hz guard tone.  
&G2 turns on CCITT 1800 Hz guard tone.  
(Not used in International models.)  
COMMAND:  
VALUES:  
DEFAULT:  
Hn  
n = 0 or 1  
n/a  
DESCRIPTION:  
H0 selects Hang Up (go on hook).  
H1 selects Go Off Hook.  
COMMAND:  
VALUES:  
DEFAULT:  
$Hn  
n = 1 thru 3  
Read Only Command  
DESCRIPTION:  
$H1 selects Help Screen #1.  
$H2 selects Help Screen #2.  
$H3 selects Help Screen #3.  
COMMAND:  
VALUES:  
DEFAULT:  
In  
n = 0,1, 2, 3 or 5  
Read Only Command  
DESCRIPTION:  
I0 requests modem ID #.  
I1 requests firmware revision #.  
I2 for Model of modem.  
I3 MTS internal use.  
I5 outputs DSP version.  
 
29  
MT2834ZPX Owner's Manual  
COMMAND:  
VALUES:  
I9  
N/A  
DEFAULT:  
Read Only Command  
DESCRIPTION:  
The I9 command is a query to display this modem's  
characteristics when operating within Windows 95.  
Entering ATI9<cr> invokes ZPX 28800 FAX CT  
on your video monitor.  
(The response to the query reveals that this modem is a  
ZPX, 28.8K, FAX and Class Two capable device.)  
COMMAND:  
VALUES:  
DEFAULT:  
L
5, 6, 7, 8, 9, 10 and 11  
Read Only Command  
DESCRIPTION:  
L5 lists all current operating parameters.  
L6 lists all current S-Register values.  
L7 lists additional parameters.  
L8 lists current on-line diagnostics.  
L9 displays Signal Strength Information.  
L10 displays Signal to Noise Ratio  
Information.  
L11 displays Noise Information.  
COMMAND:  
VALUES:  
DEFAULT:  
#Ln  
n = 0 thru 3  
#L0  
DESCRIPTION:  
#L0 selects modems to negotiate V.42 Mode.  
#L1 selects MNP on and LAP-M off.  
#L2 selects LAP-M on and MNP off.  
#L3 selects no detection phase, go directly to LAP-M.  
30  
 
Chapter 4 - AT Commands, S-Registers and Result Codes  
COMMAND:  
VALUES:  
$MBn  
n = speed  
DEFAULT:  
$MB33600 bps  
DESCRIPTION:  
$MB75 selects CCITT V.23 mode.  
$MB300 selects 300 bps on-line.  
$MB1200 selects 1200 bps on-line.  
$MB2400 selects 2400 bps on-line.  
$MB4800 selects 4800 bps on-line.  
$MB9600 selects 9600 bps on-line.  
$MB14400 selects 14400 bps on-line.  
$MB19200 selects 19200 bps on-line.  
$MB28800 selects 28800 bps on-line.  
$MB33600 selects 33600 bps on-line.  
COMMAND:  
VALUES:  
DEFAULT:  
Nd  
d = 0 thru 9  
n/a  
DESCRIPTION:  
Dial stored telephone number “d” (Do not  
include the letter D in this command.)  
COMMAND:  
VALUES:  
DEFAULT:  
NdNe  
d = 0 thru 9; e = any other number 0 thru 9  
n/a  
DESCRIPTION:  
Number Linking. If first number dialed is  
busy, another stored number may be  
automatically dialed.  
COMMAND:  
VALUES:  
DEFAULT:  
O
n/a  
n/a  
DESCRIPTION:  
Exit Command Mode and go into On-Line Mode.  
COMMAND:  
VALUES:  
P
n/a  
DEFAULT:  
Tone Dial  
DESCRIPTION:  
Modem will pulse-dial numbers following the P.  
 
31  
MT2834ZPX Owner's Manual  
COMMAND:  
VALUES:  
DEFAULT:  
&Pn  
n = 0 or 1  
&P1  
DESCRIPTION:  
&P0 selects 60-40 pulse ratio.  
&P1 selects 67-33 pulse ratio.  
COMMAND:  
VALUES:  
DEFAULT:  
Qn  
n = 0, 1 or 2  
Q0  
DESCRIPTION:  
Q0 means Result Codes sent.  
Q1 means Result Codes will be suppressed (quiet).  
Q2 means Dumb Answer Mode.  
COMMAND:  
VALUES:  
DEFAULT:  
&Qn  
n = 0 or 1  
&Q0  
DESCRIPTION:  
&Q0 selects Multi-Tech command set.  
&Q1 selects AT command set.  
COMMAND:  
VALUES:  
DEFAULT:  
Rn  
n = 0 or 1  
R0  
DESCRIPTION:  
R0 selects modem will not reverse modes.  
R1 selects modem will reverse modes.  
COMMAND:  
VALUES:  
DEFAULT:  
&Rn  
n = 0, 1 or 2  
&R1  
DESCRIPTION:  
&R0 lets Clear to Send act normally.  
&R1 forces Clear to Send on in Command Mode.  
&R2 drops for 1 second on disconnect.  
COMMAND:  
VALUES:  
DEFAULT:  
$Rn  
n = 0 or 1  
$R0  
DESCRIPTION:  
$R0 selects disconnect after 12 retransmits.  
$R1 selects do not disconnect after 12 retransmits.  
32  
 
Chapter 4 - AT Commands, S-Registers and Result Codes  
COMMAND:  
VALUES:  
DEFAULT:  
&RFn  
n = 0 or 1  
&RF1  
DESCRIPTION:  
&RF0 selects CTS follows RTS.  
&RF1 selects CTS to act independently  
COMMAND:  
VALUES:  
DEFAULT:  
Sr=n  
r = 0-11, 13, 15-17, 24-26, 29, 30, 32, 34, 36, 37, 48  
n/a  
DESCRIPTION:  
Sets value of S-Register “r” to value of “n”, where “n” is  
entered in decimal format.  
COMMAND:  
VALUES:  
DEFAULT:  
Sr?  
r = 0-11, 13, 15-17, 24-26, 29, 30, 32, 34, 36, 37, 48  
n/a  
DESCRIPTION:  
Reads value of S-Register “r” and displays value in 3-digit  
decimal format.  
COMMAND:  
VALUES:  
DEFAULT:  
$SBn  
n = speed  
$SB115200 bps  
DESCRIPTION:  
$SB300 selects 300 bps at serial port.  
$SB1200 selects 1200 bps at serial port.  
$SB2400 selects 2400 bps at serial port.  
$SB4800 selects 4800 bps at serial port.  
$SB9600 selects 9600 bps at serial port.  
$SB19200 selects 19,200 bps at serial port.  
$SB38400 selects 38,400 bps at serial port  
$SB57600 selects 57600 bps at serial port.  
$SB115200 selects 115200 bps at serial port.  
COMMAND:  
VALUES:  
DEFAULT:  
&SFn  
n = 0 or 1  
&SF0  
DESCRIPTION:  
&SF0 selects DSR follows CD.  
&SF1 selects DSR independent.  
 
33  
MT2834ZPX Owner's Manual  
COMMAND:  
VALUES:  
DEFAULT:  
&Sn  
n = 0, 1 or 2  
&S1  
DESCRIPTION:  
&S0 forces Data Set Ready On.  
&S1 lets Data Set Ready act normally.  
&S2 Data Set Ready drop is regulated by  
S24 on disconnect.  
COMMAND:  
VALUES:  
T
n/a  
DEFAULT:  
Tone Dial  
DESCRIPTION:  
Modem will tone-dial numbers following the T.  
COMMAND:  
VALUES:  
DEFAULT:  
&Tn  
n = 4 or 5  
&T5  
DESCRIPTION:  
&T4 selects Enable Response to Request for  
Remote Digital Loopback.  
&T5 selects Disable Response to Request for  
Remote Digital Loopback.  
COMMAND:  
VALUES:  
DEFAULT:  
$Tn  
n = 1 or 2  
$T1  
DESCRIPTION:  
$T0 selects calling tones on (1300 Hertz data/modem  
mode only).  
$T1 selects calling tones off (1300 Hertz data/modem  
mode only).  
COMMAND:  
VALUES:  
DEFAULT:  
#Tn  
n = 0 or 1  
#T1  
DESCRIPTION:  
#T0 turns off Trellis Coded Modulation  
#T1 turns on Trellis Coded Modulation  
34  
 
Chapter 4 - AT Commands, S-Registers and Result Codes  
COMMAND:  
VALUES:  
DEFAULT:  
Un  
n = 0, 1, 2, or 3  
n/a  
DESCRIPTION:  
U0 places modem in Analog Loop Originate Mode.  
U1 places modem in Analog Loop Answer Mode.  
U2 places modem in Remote Digital Loopback  
test mode.  
U3 places modem in Local Digital Loopback Test Mode.  
COMMAND:  
VALUES:  
DEFAULT:  
Vn  
n = 0 or 1  
V1  
DESCRIPTION:  
V0 selects Result Codes sent as digits(terse response).  
V1 selects Result Codes sent as words (verbose response).  
COMMAND:  
VALUES:  
DEFAULT:  
#Vn  
n = 0 or 1  
#V1  
DESCRIPTION:  
User can bypass V.32terbo handshaking process.  
#V0 selects V.32terbo enabled in originate/answer modes.  
#V1 selects V.32terbo disabled in originate/answer modes.  
COMMAND:  
VALUES:  
DEFAULT:  
W
n/a  
n/a  
DESCRIPTION:  
Wait for new dial-tone.  
COMMAND:  
VALUES:  
DEFAULT:  
&Wn  
n = 0 or 1  
&W1  
DESCRIPTION:  
&W0 causes modem to store its current parameters in  
nonvolatile RAM, and modem will load these for future ses-  
sions instead of reading factory ROM defaults, unless &F  
command used.  
&W1 causes modem to not store parameters.  
 
35  
MT2834ZPX Owner's Manual  
COMMAND:  
VALUES:  
DEFAULT:  
Xn  
n = 0, 1, 2, 3 or 4  
X0  
DESCRIPTION:  
X0 selects Basic Result Codes (w/o CONNECT 1200,  
CONNECT 2400).  
X1 selects Extended Result Codes (w/CONNECT 1200,  
CONNECT 2400).  
X2 selects Standard AT Command set with NO DIAL  
TONE.  
X3 selects Standard AT Command set with BUSY.  
X4 selects Standard AT Command set with NO DIAL  
TONE and BUSY.  
COMMAND:  
VALUES:  
DEFAULT:  
#Xn  
n = 0 or 1  
#X0  
DESCRIPTION:  
#X0 selects single XOFF character sent until XON level  
returns.  
#X1 selects multiple XOFF characters after buffer level is  
full.  
COMMAND:  
VALUES:  
DEFAULT:  
Yn  
n = 0 or 1  
Y0  
DESCRIPTION:  
Y0 disables sending or responding to long space “break”.  
Y1 enables sending or responding to long space “breaks”.  
COMMAND:  
VALUES:  
DEFAULT:  
Z
n/a  
n/a  
DESCRIPTION:  
All configuration parameters are reset to default values.  
COMMAND:  
VALUES:  
, (Comma)  
n/a  
DEFAULT:  
n/a  
DESCRIPTION:  
Causes pause during dialing.  
36  
 
Chapter 4 - AT Commands, S-Registers and Result Codes  
COMMAND:  
VALUES:  
DEFAULT:  
;(Semi-Colon)  
n/a  
n/a  
DESCRIPTION:  
Causes return to Command Mode after dialing.  
COMMAND:  
VALUES:  
DEFAULT:  
! (Exclamation)  
n/a  
n/a  
DESCRIPTION:  
Causes modem to flash On-Hook.  
COMMAND:  
VALUES:  
DEFAULT:  
@
n/a  
n/a  
DESCRIPTION:  
Causes modem to wait for ringback, then 5 seconds of  
silence before processing next part of command.  
COMMAND:  
VALUES:  
DEFAULT:  
+++AT<CR>  
n/a  
n/a  
DESCRIPTION:  
In-band Escape Sequence. Places modem in Command  
mode while still remaining On-Line. Enter +++ followed  
by the letters A and T, up to ten command characters, and  
a RETURN.  
COMMAND:  
VALUES:  
DEFAULT:  
BREAK AT<CR>  
n/a  
n/a  
DESCRIPTION:  
Out-of-band Escape Sequence. Places modem in Com-  
mand mode while still remaining On- Line. Not preceded by  
AT. Enter a BREAK signal, followed by the letters A and T,  
up to sixty command characters, and hit RETURN.  
 
37  
MT2834ZPX Owner's Manual  
Remote Configuration  
The Remote Configuration feature is a network management tool that  
allows you to configure modems remotely. This means you could  
configure modems anywhere in your network from one location without  
having to visit the sites or rely on remote users to follow your  
instructions. With Remote Configuration, which is protected by two  
level security, you can downline load new parameters, program new  
V.42 capabilities and implement new features. Remote Configuration  
also makes troubleshooting a remote location a lot easier.  
The way Remote Configuration works is that S-Register S13 has been  
set-up to contain the special Remote Configuration escape code.  
When calling a Remote Configuration equipped modem, you enter the  
proper Remote Escape code to enable entering your Set-up  
Password. After entering it, you can then execute AT commands as if  
you were connected locally. If you set S-Register S13 to zero,  
Remote Configuration is disabled.  
Remote Configuration Procedures  
The procedures for using the Remote Configuration features are the  
same whether or not a call originates from the remote modem. Once  
the modem is on-line, perform the procedures in Table 4-1.  
TABLE 4-1. Remote Configuration Operation Procedures  
Step  
Procedure  
1. Remote Escape Configuration requires %%%<CR> to be  
sent if the default value in S-Register S13 has not been  
changed.  
The modem responds with:  
1. - DATA Mode  
2. - COMMAND Mode  
2. You then select 1 or 2 . With 1, the modem goes  
back into data mode and with 2, the modem re-  
sponds with the following:  
Password>  
3. Enter your Set-up Password, and if the code is  
correct the modem responds with:  
OK  
38  
 
Chapter 4 - AT Commands, S-Registers and Result Codes  
TABLE 4-1 (Cont'd). Remote Configuration Operation Procedures  
You can now use any AT commands of the modem  
being remotely configured as if they were being  
entered locally. You cannot change the Set-up of the  
LOGIN Password until you enter the proper LOGIN  
Password.  
Step  
Procedure  
4. When you are done entering AT commands and you  
want to exit, type AT0 and hit RETURN. The modem  
responds with:  
1. DATA Mode  
2. COMMAND Mode  
5. Enter a 1 to go back on-line with your computer, or  
enter 2 and the correct password to talk to your  
modem.  
Password Commands  
COMMAND:  
VALUES:  
#Ixxxxxxxxxx  
n/a  
DEFAULT:  
#IMULTITECH  
DESCRIPTION:  
Login Password is any keyboard characters (x) (upper/lower  
case sensitive), minimum 6 and maximum 10 characters.  
The default Login Password is #IMULTITECH.  
COMMAND:  
VALUES:  
#Syyyyyyyyyy  
n/a  
DEFAULT:  
#SMODEMSETUP  
DESCRIPTION:  
Set-up Password is any keyboard characters (y) (upper/  
lower case sensitive), minimum 6 and maximum 10 charac-  
ters. The default Set-up Password is #SMODEMSETUP.  
 
39  
MT2834ZPX Owner's Manual  
S-Registers  
Certain Command Mode configurations are stored in memory registers  
called, S-Registers. The S command is used to assign a value to, and  
to read the current value of an S-Register. To assign a value to an S-  
Register, enter the letter S, followed by the S-Register number and an  
equals sign (=). To read an S-Register value, enter the letter S  
followed by the S-Register number and a question mark (?), then hit  
RETURN. To verify that the S-Register value was entered correctly,  
enter for example, ATS8? and hit RETURN. You should receive a  
response of the assigned value given to that S-Register.  
S0  
Number of Rings Until Modem Answers  
Unit: 1 ring  
Range: 0-255  
Default:  
0
Description: Sets the number of rings before the modem answers.  
S1  
Rings Which Have Occurred  
Unit: 1 ring  
Range: 0-255  
Default:  
0
Description: Counts the number of rings that have occurred.  
S2  
Escape Code Character  
Unit: ASCII Character  
Range: 0-127  
Default: 43 (+ sign)  
Description: Defines the escape code character.  
40  
 
Chapter 4 - AT Commands, S-Registers and Result Codes  
S3  
Return Character  
Unit: ASCII Character  
Range: 0-127  
Default: 13  
Description: Defines the character recognized as Carriage Return (RE-  
TURN) or “Enter”.  
S4  
Line Feed Character  
Unit: ASCII Character  
Range: 0-127  
Default: 10  
Description: Defines the character recognized as LINE FEED.  
S5  
Backspace Character  
Unit: ASCII Character  
Range: 0-127  
Default:  
8
Description: Defines the character recognized as BACKSPACE.  
S6  
Wait Time for Dial Tone  
Unit: 1 second  
Range: 2-255, 4-255**  
Default: 2, 4**  
Description: Sets the time the modem waits after the RETURN key is pressed  
before executing a dial command.  
S7  
Time for Carrier (Abort Timer)  
Unit: 1 second  
Range: 1-255, 1-45*  
Default: 45  
Description: Defines the Abort Timer (lack of carrier) delay time.  
* Value for International and DOC units  
** Value for International Units only  
 
41  
MT2834ZPX Owner's Manual  
S8  
Pause Time for Comma  
Unit: 1 second  
Range: 0-255, 4-255**  
Default: 2, 4**  
Description: Sets the length of the pause caused by a comma inserted in a  
dialing command.  
S9  
Carrier Detect Response Time  
Unit: 100 mSec.  
Range: 1-255  
Default:  
6
Description: Sets the time delay for when the modem first detects a valid  
incoming carrier signal and when the modem turns on its Carrier  
Detect circuit.  
S10  
Carrier Loss Disconnect Delay Time  
Unit: 100 mSec.  
Range: 0-255  
Default:  
7
Description: Sets the time a carrier signal must be lost before the modem  
disconnects.  
S11  
Tone Dialing: Tone Spacing and Duration  
Unit: 1 mSec.  
Range: 1-255, 80-255*  
Default: 70, 80*  
Description: Sets the time duration of spacing between tone in tone-dialing.  
* Value for International and DOC units  
** Value for International Units only  
42  
 
Chapter 4 - AT Commands, S-Registers and Result Codes  
S13  
Remote Configuration Escape Character  
Unit: ASCII Character  
Range: 0-127  
Default: 37 (% sign)  
Description: Defines the remote configuration escape character.  
S17  
Changing Break Time  
Unit: 10 mSec.  
Range: 0-2.5 sec  
Default: 250  
Description: S17 defines the break time (space) to local PC.  
S24  
PBX/CBX Disconnect Drop Time for DSR/CTS/CD  
Unit: 50 mSec.  
Range: 0-255  
Default: 20  
Description: Defines DSR/CTS/CD dropout time. The default of 20 equals  
one second.  
S25  
DTR Dropout Time  
Unit: 100 mSec.  
Range: 0, 1 through 255  
Default:  
0
Description: Defines DTR dropout time. 0 default equals 50ms.  
S26  
Failed Password Attempts  
Unit: 1 failed attempt  
Range: 0-255  
Default:  
0
Description:Counts the number of times there has been a failed password attempt.  
 
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MT2834ZPX Owner's Manual  
S29  
Local Inactivity Timer  
Unit: minutes  
Range: 1-255  
Default: 20  
Description: Defines the amount of idle time that can elapse between AT  
commands after the SETUP password has been entered.  
S30  
Inactivity Timer  
Unit: 1 minute  
Range: 0-255  
Default:  
0
Description: Inactivity timer used to disconnect the modem.  
S32  
Time Elapse for Escape Sequence  
Unit: 1 second  
Range: 0-255  
Default: 20  
Description: Sets the duration in which modem waits for a <CR> to be entered  
during escape sequence execution.  
S34  
Buffer Length of Command Mode...After On-line Escape Sequence  
Unit: ASCII Character  
Range: 0-60  
Default: 10  
Description: Sets buffer length of command mode after on-line escape  
sequence.  
44  
 
Chapter 4 - AT Commands, S-Registers and Result Codes  
S36  
Time Between DTR Inactive and Modem Off-Hook  
Unit: 1 Second  
Range: 0-255 seconds  
Default:  
0
Description: Sets the time between DTR inactive (low) and the modem going  
off-hook. The DTR Busy-out feature is disabled with S36=0.  
S37  
Time Between DTR Active and Modem On-Hook  
Unit: 1 Second  
Range: 0-255 seconds  
Default:  
5
Description: Sets the time between DTR being active and the modem going  
on-hook (not busy).  
S48  
Program V.34 Connect Speeds  
Unit: N/A  
Range: 33, 31, 28, 26, 21, 19, 16, 14, 12, 9 and 4  
Default:  
0
Description: Defines which speed modem connects within V.34 mode scope  
(e.g., S48 = 21 means maximum connect speed is 21.6K). This  
register compensates for line conditions that will not support  
higher V.34 speeds (e.g., 33.6K, 31.2K, 28K, 26.4K, 24K...).  
The modem default is a value of 0, which indicates a connection  
attempt of 33.6K.  
 
45  
MT2834ZPX Owner's Manual  
Result Codes  
The MT2834ZPX Command mode provides you with several  
responses, or “Result Codes”, that can aid you in Command mode  
operation. These Result Codes are displayed on your video monitor.  
AT&Q0 selects Multi-Tech responses with Reliable/LAP-M/  
Compressed modifiers. The terse result code for CONNECT 2400 is  
9.  
AT&Q1 selects Standard AT command set responses. The terse  
result code for CONNECT 2400 is 10. The following tables list result  
codes generated by the &Q command.  
Table 4-2 &Q0 "Multi-Tech" Result Codes  
TERSE  
0
VERBOSE  
OK  
1
CONNECT  
2
RING  
3
4
NO CARRIER  
ERROR  
5*  
6
7
CONNECT 1200  
NO DIALTONE  
BUSY  
8
9*  
NO ANSWER  
CONNECT 2400  
CONNECT 4800  
CONNECT 9600  
CONNECT 14400  
CONNECT 19200  
CONNECT 21600  
CONNECT 24000  
CONNECT 26400  
CONNECT 28800  
CONNECT 31200  
CONNECT 33600  
11*  
12*  
13*  
19*  
21*  
24*  
26*  
28*  
31*  
33*  
* With MNP error correction on, RELIABLE (or R) is added to these  
result codes. With LAP-M error correction on, LAP-M (or L) is added  
to these result codes. With data compression on, COMPRESSED (or  
C) is added. (Note these "Extended" Result Codes are displayed when  
your modem is set-up to do so with an X1, X2, X3, or X4 command.)  
46  
 
Chapter 4 - AT Commands, S-Registers and Result Codes  
Table 4-3 &Q1 "Standard AT" Result Codes  
TERSE  
0
VERBOSE  
OK  
1
CONNECT  
2
RING  
3
4
NO CARRIER  
ERROR  
5
6
7
CONNECT 1200  
NO DIAL TONE  
BUSY  
8
NO ANSWER  
CONNECT 2400  
CONNECT 4800  
CONNECT 9600  
CONNECT 14400  
CONNECT 19200  
CONNECT 21600  
CONNECT 24000  
CONNECT 26400  
CONNECT 28800  
CONNECT 31200  
CONNECT 33600  
10  
11  
12  
13  
19  
21  
24  
26  
28  
31  
33  
*Error Correction/Data Compressed modifiers are not displayed with  
Standard AT Result Codes.  
 
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MT2834ZPX Owner's Manual  
AT Commands and S-Register Summary  
The vast majority of installations are similar, with the MT2834ZPX  
being used to dial up a remote installation where the call is  
automatically answered. Your MT2834ZPX has a default configuration  
to dial another 33,600 bps modem that support error correction, data  
compression and flow control. If the answering modem is not  
compatible, the MT2834ZPX can match protocols, provided the  
protocols are industry standard (i.e., ITU-T, AT&T or Bell) and not  
proprietary.  
AT&W0 (or AT&W) command, used in conjunction with specific other  
AT commands and S-Registers, can reconfigure the MT2834ZPX to  
conform to a specific application. The MT2834ZPX can store its  
configuration parameters and S-Register values in its nonvolatile  
memory (RAM). This command also sets the modem upon power up,  
or when it is reset with an ATZ command, the modem reads all its  
configuration and S-Register parameters from RAM, and not from the  
factory settings in ROM (note you may recall factory installed defaults  
by entering AT&F8&W0).  
The &W command changes the configuration parameters stored in  
RAM that you specifically intend to alter. All other default parameters  
remain unchanged.  
The AT&W1 command sets the modem so that it does not store its  
parameters in RAM, and on power up or when an ATZ command is  
issued, parameters are read from the factory default settings in ROM.  
You may first view the modem's current operating parameters by using  
the ATL5, ATL6 and ATL7 commands to display the current modem  
configuration; then alter the modem's configuration settings if your  
application requires you to do so.  
48  
 
Chapter 5 - Troubleshooting  
Chapter 5 - Troubleshooting  
Troubleshooting  
Your MT2834ZPX was thoroughly tested at the factory before it was  
shipped. If you are unable to make a successful connection or if you  
experience data loss or garbled characters during your connection, it  
is possible that the modem is defective. However, it is more likely that  
the source of your problem lies elsewhere. Problems you may  
encounter include the following:  
The modem does not respond to commands.  
The modem dials but is unable to make a connection.  
The modem disconnects while online.  
The modem cannot connect when answering.  
File transfer is slower than it should be.  
Losing data.  
Getting garbage characters on the monitor.  
Can’t run fax and communications software at the same time.  
If you experience problems, please check the following possibilities  
before calling Tech Support (see Chapter 7).  
The Modem Does Not Respond to Commands  
Make sure you are issuing the modem commands from the data  
communications software, either manually in terminal mode or  
automatically by configuring the software. (You cannot send  
commands to the modem from the DOS prompt.)  
Make sure you are in terminal mode in your data communications  
program, then type AT and press ENTER. If you get an OK  
response, your connections are good and the problem likely is in  
your phonebook entry or session settings.  
Try resetting your modem by turning it off and on. Make sure there  
is a reset command (&F) in your initialization string, or your  
modem may not initialize correctly.  
If you don’t get an OK, the problem may still be in the  
communications software. Make sure you have done whatever is  
necessary in your software to make a port connection. Not all  
communications programs connect to the COM port automatically.  
 
49  
MT2834ZPX Owner's Manual  
Some connect when the software loads and remain connected  
until the program terminates. Others, like MultiExpress Terminal,  
can disconnect without exiting the program (make sure the  
Connect icon looks plugged in). MultiExpress Terminal also allows  
multiple terminals to be open, but only one can access the modem  
at a time. If MultiExpress Terminal reports that it cannot make a  
connection, click on the Window menu to see if more than one  
terminal is open.  
Your communications software settings may not match the port  
the modem is connected to. Or you may have selected a COM  
port in your software other than the one the modem is connected  
to—compare the settings in your software to the connection.  
Peripheral expansion cards, such as bus mouse and sound cards,  
may include a serial port preconfigured as COM1 or COM2. The  
extra serial port, or the card itself, may use the same COM port,  
memory address, or interrupt request (IRQ) as your  
communications port. Be sure to disable any unused ports.  
To look for address or IRQ conflicts if you use Windows 3.1x,  
select File, Run in Program Manager, type MSD, and press  
ENTER. Then select Mouse, COM Ports, and IRQ Status and note  
the addresses and IRQs that are in use. If you find an IRQ  
conflict, note which IRQs are not being used, then change one of  
the conflicting devices to use one of the unused IRQs. If you find  
an address conflict, change the address of one of the conflicting  
devices.  
To change a port address or IRQ in Windows 3.1x, double-click  
the Control Panel icon, then the Ports icon. Click on the port you  
want to change, click Settings, click Advanced, and select the new  
port address and/or interrupt. If you wish to use COM3 or COM4,  
note that COM3 shares an IRQ with COM1, as does COM4 with  
COM2, so you should change their IRQs to unused ones, if  
possible.  
If you use Windows 95, right-click on My Computer, select  
Properties from the menu, click on the Device Manager tab,  
double-click on Ports, then double-click on the Communications  
Port your modem is connected to. In the port’s Properties sheet,  
click on the Resources tab to see the port’s Input/Output range  
and Interrupt Request. If another device is using the same  
address range or IRQ, it will appear in the Conflicting Device List.  
50  
 
Chapter 5 - Troubleshooting  
Uncheck Use Automatic Settings to change the port’s settings so  
they do not conflict with the other device, or select the port the  
conflicting device is on and change it instead. If you need to open  
your computer to change switches or jumpers on the conflicting  
device; refer to the device’s documentation.  
The modem may be defective. If you have another Multi-Tech  
modem, try swapping modems. If the problem goes away, the first  
modem is possibly defective. Call Tech Support for assistance  
(see Chapter 7).  
The Modem Dials But Cannot Make a Connection  
There can be several reasons the ZPX fails to make a connection.  
Possibilities include  
lack of a physical connection to the telephone line.  
a wrong dial tone.  
a busy signal.  
a wrong number.  
no modem at the other end.  
a faulty modem, computer, or software at the other end.  
incompatibility between modems.  
You can narrow the list of possibilities by using extended result codes.  
To enable them, enter ATV1X4 and press ENTER while in terminal  
mode, or include V1X4 in the modem’s initialization string. When you  
dial again, the modem will report the call’s progress.  
If the modem reports NO DIALTONE, check that the modem’s  
telephone line cable is connected to both the modem’s LINE jack  
(not the PHONE jack) and the telephone wall jack. If the cable  
looks secure, try replacing it. If that doesn’t work, the problem may  
be in your building’s telephone installation. To test the building  
installation, plug a telephone into your modem’s telephone wall  
jack and listen for a dial tone. If you hear a dial tone, your modem  
may be installed behind a company phone system (PBX) with an  
internal dial tone that sounds different from the normal dial tone.  
In that case, the modem may not recognize the dial tone and may  
treat it as an error.  
Check your PBX manual to see if you can change the internal dial  
tone; if you can’t, change your modem’s initialization string to  
replace X4 with X3, which will cause the modem to ignore dial  
tones.  
 
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MT2834ZPX Owner's Manual  
If the modem reports BUSY, the other number may be busy, in  
which case you should try again later, or it may indicate that you  
have failed to add a 9, prefix to the phone number if you must dial  
9 for an outside line.  
If you must dial 9 to get an outside line, the easiest way to dial it  
automatically is to include it in the modem’s dial prefix, e.g.,  
ATDT9,. Note the comma, which inserts a pause before the  
number is dialed. By inserting 9, into the dial prefix, you do not  
have to include it in each directory entry in MultiExpress Terminal.  
To change the dial prefix in MultiExpress Terminal, select Setup,  
Modem; then select the modem type you are using, and type the  
new prefix in the Dial Prefix box. To change the dial prefix in  
Windows Terminal, select Settings, Modem Commands. To  
change it in Windows 95 HyperTerminal, select Call, Connect  
from the menu bar, click Dialing Properties, and type 9 in the local  
and long distance boxes in How I Dial from This Location.  
If the modem reports NO ANSWER, the other system has failed to  
go off-hook, or you might have dialed a wrong number. Check the  
number.  
If the modem reports NO CARRIER, the phone was answered at  
the other end, but no connection was made. You might have  
dialed a wrong number, and a person answered instead of a  
computer, or you might have dialed the correct number but the  
other computer or software was turned off or faulty. Check the  
number and try again, or try calling another system to make sure  
your modem is working. Also, try calling the number on your  
telephone. If you hear harsh sounds, then another modem is  
answering the call, and the modems may be having problems  
negotiating because of modem incompatibilities or line noise. Try  
connecting at a lower speed.  
52  
 
Chapter 5 - Troubleshooting  
The Modem Disconnects While Online  
If you have call waiting on the same phone line as your modem, it  
may interrupt your connection when someone tries to call you. If  
you have call waiting, disable it before each call. In most  
telephone areas, you can disable call waiting by preceding the  
telephone number with *70 (check with your local telephone  
company).  
You can automatically disable call waiting by including the  
disabling code in the modem’s dial prefix (e.g., ATDT*70,—note  
the comma, which inserts a pause before the number is dialed).  
To change the dial prefix in MultiExpress Terminal, select Setup,  
Modem; then select the modem type you are using, and type the  
new prefix in the Dial Prefix box. To change the dial prefix in  
Windows Terminal, select Settings, Modem Commands. To  
change it in Windows 95 HyperTerminal, select Call, Connect  
from the menu bar, click Dialing Properties, check this location  
has Call Waiting, and select the correct code for your phone  
service.  
If you have extension phones on the same line as your modem,  
you or someone else can interrupt the connection by picking up  
another phone. If this is a frequent problem, disconnect the  
extension phones before using the modem, or install another  
phone line especially for the modem.  
Check for loose connections between the modem and the  
computer.  
You may have had a poor connection because of line conditions  
or the problem may have originated on the other end of the line.  
Try again.  
If you were online with a BBS, it may have hung up on you  
because of lack of activity on your part or because you exceeded  
your time limit for the day. Try again.  
 
53  
MT2834ZPX Owner's Manual  
The Modem Cannot Connect When Answering  
Auto-answer may be disabled. Turn on auto-answer in your  
datacomm program or send the command ATS0=1 to your  
modem in terminal mode.  
File Transfer Is Slower Than It Should Be  
If you are using a slow transfer protocol, such as Xmodem or  
Kermit, try Zmodem or Ymodem/G instead.  
Is your line noisy? If there is static on your line, the modem has to  
resend many blocks of data to insure accuracy. You must have a  
clean line for maximum speed.  
Are you downloading a compressed file with MNP 5 hardware  
compression enabled? Since hardware data compression cannot  
compress a file already compressed by an archiving program, the  
transfer can be marginally slower with data compression enabled  
than with it disabled.  
Try entering the L8 (List Online Diagnostics) command in online  
mode, making a screen print of the diagnostics listing, and  
checking for parameters that may be unacceptable (number of  
retrains, round trip delay, etc.).  
Losing Data  
If you are using data compression and a high speed serial port,  
set the serial port baud rate to four times the data rate.  
Make sure the flow control method you selected in software  
matches the method selected in the modem. If you have a  
Macintosh, you may have the wrong cable for hardware flow  
control.  
If you are running under Windows 3.1 and have a 16550AFN  
UART, you may need to turn on the 16550’s data buffers and/or  
replace the Windows serial driver, COMM.DRV.  
Try entering the L8 (List Online Diagnostics) command in online  
mode, making a screen print of the diagnostics listing, and  
checking for parameters that may be unacceptable (number of  
retrains, round trip delay, etc.).  
54  
 
Chapter 5 - Troubleshooting  
Getting Garbage Characters on the Monitor  
Your computer and the remote computer may be set to different  
word lengths, stop bits, or parities. If you have connected at 8-N-  
1, try changing to 7-E-1, or vice-versa, using your communications  
software.  
You may be experiencing line noise. Enable error correction, if it  
is disabled, or hang up and call again; you may get a better  
connection.  
At speeds above 2400 bps, the remote modem might not use the  
same transmission or error correction standards as your modem.  
Try connecting at a slower speed or disabling error correction.  
(With no error correction, however, line noise can cause garbage  
characters.)  
Try entering the L8 (List Online Diagnostics) command in online  
mode, making a screen print of the diagnostics listing, and  
checking for parameters that may be unacceptable (number of  
retrains, round trip delay, etc.).  
Fax and Communications Software Won’t Run at  
the Same Time  
Communications devices can be accessed by only one application at a  
time. Under DOS or Windows 3.1x, you can run either your fax  
software or your datacomm software, but not both at the same time,  
unless you have a special communications device management  
application, such as Multi-Tech’s Virtual Modem Driver. In Windows  
95, you can have data and fax communication applications open at the  
same time, but they cannot use the same modem at the same time.  
In this test, data from your computer or terminal is sent to your  
modem's transmitter, converted into analog form, looped back to the  
receiver, converted into digital form and then received back at your  
monitor for verification. No connection to the phone line is required.  
See Figure 6-1 in Chapter 6.  
 
55  
MT2834ZPX Owner's Manual  
Chapter 6 - Testing Your Modem  
Local Analog Loopback Test/V.54 Loop 3  
In this test, data from your computer or terminal is sent to your  
modem's transmitter, converted into analog form, looped back to the  
receiver, converted into digital form and then received back at your  
monitor for verification. No connection to the phone line is required.  
See Figure 6-1.  
Figure 6-1. Local Analog Loopback Test  
The test procedure is as follows:  
1. Connect the modem to your computer. With your communication  
software, set the desired baud rate.  
2. Type ATU0 (or ATU) and hit ENTER. This places your modem in  
Analog Loopback mode, in the Originate mode. The modem is  
now out of the Command mode and in a pseudo On-Line mode.  
3. Once you receive a connect message (if responses are enabled),  
enter data from your keyboard. For this test, typing multiple upper  
case "U" characters is a good way to send an alternating test  
pattern of ones and zeros.  
4. For a more complete test, you should also test the modem in  
Answer mode. To do this, you must “escape” from Originate mode  
by entering an Escape Sequence (+++AT<CR> or  
<BREAK>AT<CR>) . Then type ATU1 and hit ENTER to place  
the modem in Analog Loopback mode, in the Answer mode. Then  
repeat step 3.  
56  
 
Chapter 6 - Testing Your Modem  
5. Your modem passes this test if the data entered from your  
keyboard are the same as the data received on your monitor. If  
different data is appearing on your monitor, your modem is  
probably causing the problem, although it could also be your  
computer. If your modem passes this test, but you are receiving  
errors while On-line, the remote modem or the phone line could  
be at fault.  
Note: All Loopback Tests operate at all speeds except 300 bps; and  
disable error correction (&E0&W0<cr>) before engaging in loopback  
tests.  
Digital Loopback Test/V.54 Loop 2 (Local/Manual)  
The Digital Loopback Test is an on-line test that loops data sent from  
one modem across the phone line to another modem, then back to the  
first modem. See Figure 6-2.  
There are two ways to put a modem into Digital Loopback mode.  
1. Locally or Manually, described here in section 6.2.  
2. Remotely or Automatically, see section 6.3.  
In this test the local modem is placed in Digital Loopback mode. Data  
is entered and transmitted from the remote modem (which is not in  
digital loopback mode), sent across the phone line to the local modem  
and looped back to the remote modem.  
The test procedure is as follows:  
1. Go into Terminal mode. Type AT and hit ENTER; you should get  
an OK message.  
2. Dial the remote modem by entering the Dial command and the  
phone number, to establish On-line mode.  
3. Type the Escape Sequence (+++AT<CR> or <BREAK>AT<CR>)  
which brings your modem into Command mode, while still  
maintaining the pseudo On-line mode with the remote modem.  
4. Type ATU3 from the local PC and hit ENTER. Once you receive  
an OK message from your modem (if responses are enabled), the  
local modem is placed in Digital Loopback mode.  
 
57  
MT2834ZPX Owner's Manual  
5. Data is typed from the remote keyboard. For this test, typing  
multiple upper case "U" characters is a good way to send an  
alternating test pattern of ones and zeros. The data received by  
the local modem will enter its analog receiver, be converted to  
digital data, be reconverted into analog, and then looped through  
its transmitter back to the remote modem. Your modem passes  
this test if the data entered from the remote keyboard is the same  
as the data received on the remote monitor.  
Figure 6-2. Digital Loopback Test (local/manual)  
6. When testing is complete, you may end the test by typing an  
Escape Sequence (+++AT<CR> or <BREAK>AT<CR>) to bring  
your modem into Command mode. The modem should respond  
with an OK message. If you wish to stay On-line with the remote  
modem for normal data transmission, type AT0 and hit ENTER. If  
you wish to terminate the call, type ATH and hit ENTER to hang  
up.  
Digital Loopback Test/V.54 Loop 2 (Remote/  
Automatic)  
In this test, your modem must be On-line with another modem set up  
to respond to a request for Digital Loopback (note that some modems  
may not support Remote Loopback or may have this feature disabled).  
The test procedure is as follows:  
1. Go into Terminal mode. Type AT and hit ENTER; you should get  
an OK message.  
2. Dial the remote modem by entering the Dial command and the  
phone number, to establish On-line mode.  
58  
 
Chapter 6 - Testing Your Modem  
Note: The &T4 command must be set on the remote modem to run  
this test.  
3. Type the Escape Sequence (+++AT<CR> or <BREAK>AT<CR>)  
which brings your modem into Command mode, while still  
maintaining the connection with the remote modem.  
4. Type ATU2 and hit ENTER. The local modem responds to this  
command by transmitting an unscrambled marking signal, which  
causes the remote modem to place itself in Digital Loopback  
mode. Then the local modem exits Command mode and enters  
pseudo On-line mode.  
5. Type data from your keyboard. For this test, typing multiple upper  
case "U" characters is a good way to send an alternating test  
pattern of ones and zeros. The data received by the remote  
modem will enter its analog receiver, be converted to digital data,  
be reconverted into analog, and then looped through its  
transmitter back to the local modem. Your modem passes this test  
if the data entered from the local keyboard is the same as the  
data received on your monitor.  
Figure 6-3. Digital Loopback Test (remote/automatic)  
 
59  
MT2834ZPX Owner's Manual  
Chapter 7 - Service, Warranty and Tech Support  
Introduction  
This chapter starts out with statements about your modem's 10-year  
warranty. The next section, Tech Support, should be read carefully if  
you have questions or problems with your modem. It includes the  
technical support telephone numbers, space for recording your  
modem information, and an explanation of how to send in your modem  
should you require service. The final two sections explain how to use  
our Bulletin Board Service (BBS), and a brief section on the  
CompuServe/Internet Forums.  
Limited Warranty  
Multi-Tech Systems, Inc. (“MTS”) warrants that its products will be free  
from defects in material or workmanship for a period of ten years from  
the date of purchase, or if proof of purchase is not provided, ten years  
from date of shipment. MTS MAKES NO OTHER WARRANTY,  
EXPRESSED OR IMPLIED, AND ALL IMPLIED WARRANTIES OF  
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE  
ARE HEREBY DISCLAIMED. This warranty does not apply to any  
products which have been damaged by lightning storms, water, or  
power surges or which have been neglected, altered, abused, used for  
a purpose other than the one for which they were manufactured,  
repaired by the customer or any party without MTS’s written  
authorization, or used in any manner inconsistent with MTS’s  
instructions.  
MTS’s entire obligation under this warranty shall be limited (at MTS’s  
option) to repair or replacement of any products which prove to be  
defective within the warranty period, or, at MTS’s option, issuance of a  
refund of the purchase price. Defective products must be returned by  
Customer to MTS’s factory transportation prepaid.  
MTS WILL NOT BE LIABLE FOR CONSEQUENTIAL DAMAGES AND  
UNDER NO CIRCUMSTANCES WILL ITS LIABILITY EXCEED THE  
PURCHASE PRICE FOR DEFECTIVE PRODUCTS.  
60  
 
Chapter 7 - Service, Warranty and Tech Support  
On-line Warranty Registration  
To register your Multi-Tech product on-line, click on the following link:  
Tech Support  
Multi-Tech has an excellent staff of technical support personnel  
available to help you get the most out of your Multi-Tech product. If  
you have any questions about the operation of this unit, call 1-800-  
972-2439. Please fill out the modem information (below), and have it  
available when you call. If your modem requires service, the tech  
support specialist will guide you on how to send in your modem (see  
Service Section).  
Recording Modem Information  
Please fill in the following information on your Multi-Tech modem. This  
will help tech support in answering your questions.  
Modem Model No.: __________________________________  
Modem Serial No.: __________________________________  
Modem Firmware Version: ____________________________  
FAX Software Version: _______________________________  
DataComm Software Version: _________________________  
COM Port #: _______________________________________  
IRQ Setting: _______________________________________  
The modem model and serial numbers are silkscreened on the bottom  
of your modem. The software versions are printed on the diskette  
labels. Type ATI1 to display the modem firmware version.  
Please note the status of your modem before calling tech support. This  
screen messages, diagnostic test results, problems with a specific  
application, etc. Use the space below to note modem status:  
 
61  
MT2834ZPX Owner's Manual  
Service  
If your tech support specialist decides that service is required,  
modems may be sent (freight prepaid) to our factory. Return shipping  
charges will be paid by Multi-Tech Systems (within North America).  
Include the following with your modem:  
a description of the problem.  
return billing and return shipping addresses.  
contact name and phone number.  
check or purchase order number for payment if the modem is out  
of warranty. (The standard repair charge for this modem is $95.  
This price is valid at the time of this publication but could change  
in the future. Check with your technical support specialist.)  
if possible, note the name of the technical support specialist with  
whom you spoke.  
If you need to inquire about the status of the returned product, be  
prepared to provide the serial number of the product sent (see  
previous section).  
Send modems to this address:  
MULTI-TECH SYSTEMS, INC.  
2205 WOODALE DRIVE  
MOUNDS VIEW, MINNESOTA 55112  
ATTN: SERVICE OR REPAIRS  
62  
 
Chapter 7 - Service, Warranty and Tech Support  
About the Multi-Tech BBS  
For customers who do not have Internet access, Multi-Tech maintains  
a bulletin board system (BBS) that mirrors its FTP site. Information  
available from the BBS includes new product information, product  
upgrade files, and problem-solving tips. The phone number for the  
Multi-Tech BBS is (800) 392-2432 (USA and Canada) or (612) 785-  
3702 (international and local).  
The BBS can be accessed by any asynchronous modem operating at  
1200 bps to 33,600 bps at a setting of 8 bits, no parity, and 1 stop bit  
(8-N-1).  
To log on to the Multi-Tech BBS  
1. Set your communications program to 8-N-1.  
2. Dial our BBS at (800) 392-2432 (USA and Canada) or (612) 785-  
3702 (international and local).  
3. At the prompts, type your first name, last name, and password;  
then press ENTER. If you are a first time caller, the BBS asks if  
your name is spelled correctly. If you answer yes, a questionnaire  
appears. You must complete the questionnaire to use the BBS on  
your first call.  
4. Press ENTER until the Main Menu appears. From the Main Menu  
you have access to two areas: the Files Menu and News. For help  
on menu commands, type ?.  
To Download a file  
If you know the file name  
1. From the Main Menu, type F to access the Files Menu, then type  
D.  
2. Enter the name of the file you wish to download from the BBS.  
3. If a password is required, enter the password.  
4. Answer Y or N to the automatic logoff question.  
5. Select a file transfer protocol by typing the indicated letter, such  
as Z for Zmodem (the recommended protocol).  
6. If you select Zmodem, the transfer will begin automatically. If you  
select another protocol, you may have to initiate the transfer  
yourself. (In most datacomm programs, the PAGE DOWN key  
initiates the download.)  
 
63  
MT2834ZPX Owner's Manual  
7. When the download is complete, press ENTER to return to the  
File Menu.  
8. To exit the BBS, type G and press ENTER.  
If you don’t know the file name  
1. From the Main Menu, type F to access the Files Menu. For a list of  
file areas, type L, press ENTER, then type L and press ENTER  
again. (If you do not type the second L, you will list all of the files  
on the BBS.)  
2. Mark each file area you would like to examine by typing its list  
number and pressing ENTER.  
3. Enter L to list all the files in the selected file areas. Enter C to go  
forward in the file list and P to go back.  
4. To mark one or more files for download, type M, press ENTER,  
type the list numbers of the files, and press ENTER again.  
5. Enter D. You will see a list of the files you have marked. Enter E if  
you would like to edit the list; otherwise enter D again to start the  
download process.  
6. Select a file transfer protocol by typing the indicated letter, such  
as Z for Zmodem (the recommended protocol).  
7. If you select Zmodem, the file will transfer automatically. If you  
select another protocol, you may have to initiate the transfer  
yourself. (In most data communications programs, the PAGE  
DOWN key initiates the download.)  
8. When the download is complete, press ENTER to return to the  
File Menu.  
9. To exit the BBS, type G and press ENTER.  
64  
 
Chapter 7 - Service, Warranty and Tech Support  
About CompuServe/Internet  
In addition to the BBS, Multi-Tech provides support through  
CompuServe's Modem Vendor Forum (GOMODEMVEN) under GO  
MULTITECH. Refer to your CompuServe documentation for special  
operating procedures.  
Multi-Tech is a commercial provider on the Internet, and we retrieve  
e-mail messages from the following mailboxes on a periodic basis:  
Marketing Dept.  
Sales Dept.  
International Marketing &  
Sales  
Publications Dept.  
If you prefer to receive support via the internet you can contact tech  
support via e-mail at:  
Multi-Tech's presence includes a Web site at:  
and an ftp site at:  
The ftp server mirrors the Multi-Tech BBS.  
About the Multi-Tech Fax-Back Service  
Multi-Tech's fax-back system provides 24-hour access to sales,  
marketing, and technical literature. Dial 612-717-5888, follow the  
voice prompts, and request document number 10 for a catalog of  
available documents.  
For convenience, have your fax number handy: __________________  
From the catalog of available documents, you can order newsletters,  
white papers, press releases, etc. from the sales and marketing index  
(pages 1-4), or order basic modem operation and troubleshooting  
guides from the technical support and engineering index. Just enter  
the applicable FB Doc. # from the left column of the catalog.  
 
65  
MT2834ZPX Owner's Manual  
Appendix A - Technical Specifications  
Your MT2834ZPX data/fax modem meets the specifications listed  
below:  
Model Numbers  
MT2834ZPX  
Data Rates (modem)  
33,600, 31,200, 28,800, 26,400,  
24,000, 21,600, 19,200, 16,800,  
14,400, 12,000, 9600, 7200, 4800,  
2400, 1200, 0-300 bps  
Data Rates (fax)  
Data Format  
14,400, 9600, 7200, 4800 bps  
Serial, binary, asynchronous at 0-300,  
1200, 2400, 4800, 7200, 9600, 14,400,  
16,800 or 19,200, 21,600, 24,000,  
26,400, 28,800, 31,200, 33,600 bps  
Compatibility  
ITU V.42bis, V.42, Enhanced V.34,  
AT&T V.32terbo, ITU V.32bis, V.32,  
V.21*, V.22bis, V.22, V.23*, Bell 212A  
and 103/113, ITU V.17, Group 3 T.4,  
T.30 and EIA TR-29 Class 2 (*V.21/  
V.23 Int'l models only)  
Error Correction  
V.42 (LAP-M or MNP 3 & 4) error  
correction  
Data Compression  
V.42bis, (4:1 throughput) or  
MNP 5 (2:1 throughput) data  
compression  
Speed Conversion  
Flow Control  
Serial port data rates adjustable to 300,  
1200, 2400, 4800, 9600, 19,200,  
38,400, 57,600 and 115,200 bps  
Xon/Xoff, Hardware RTS/CTS, ENQ/  
ACK,  
Options  
Mode of Operation  
Full duplex over dial-up lines automatic  
dialing and answer  
66  
 
Appendix A - Technical Specifications  
Intelligent Features  
Fully “AT command” compatible,  
microprocessor controlled remote  
configuration, EIA extended Automode,  
adaptive line probing, automatic symbol  
rate and carrier frequency during start-  
up, retrain and rate renegotiation,  
autodial, redial, repeat dial, dial linking,  
pulse or tone dial, dial pauses, call  
status display, auto-parity and data rate  
selection, keyboard-controlled modem  
options, non-volatile memory and on-  
screen displays for modem option  
parameters and up to ten telephone  
numbers/command lines of up to 60  
digits each, help menus  
Command Buffer  
Modulation  
60 characters  
Trellis Coded Modulation (TCM) at  
33,600, 31,200, 28,800, 26,400,  
24,000, 21,600, 19,200, 16,800,  
14,400, 12,000 and 9600 bps,  
Quadrature Amplitude Modulation  
(QAM) at 9600 (non-trellis), 4800 and  
2400 bps, PSK at 1200 bps, FSK at  
300 bps  
Fax Modulations  
V.21CH2 FSK at 300 bps  
V.27ter DPSK at 4800 and 2400 bps  
V.29 QAM at 9600 and 7200 bps  
V.17 TCM at 14400, 12000, 9600, and  
7200 bps  
Fax Carrier  
V.21CH2 (Half Duplex)  
Frequencies  
1650Hz Mark, 1850Hz Space for  
Transmit Originate  
1650Hz Mark, 1850Hz Space for  
Transmit Answer  
V.27ter 1800Hz Originate/Answer  
V.29 QAM 1700Hz Originate/Answer  
V.17 TCM 1800Hz Originate/Answer  
 
67  
MT2834ZPX Owner's Manual  
Carrier Frequencies(Data) 1800 Hz V.32/V.32bis/V.32terbo/  
Enhanced V.34  
33.6K/31.2K/28.8K/26.4K/24K/21.6K/  
19.2K/16.8K/14.4K/12K/9.6K/4.8K  
Carrier Frequencies  
2400 & 1200 bps  
(V.22bis/V.22 or  
Bell 212A Standard)  
Transmit Originate:  
Transmit Answer:  
Receive Originate:  
Receive Answer:  
1200 Hz  
2400 Hz  
2400 Hz  
1200 Hz  
Carrier Frequencies,  
300 bps(Bell Standard)  
1270 Hz Mark, 1070 Hz Space for  
Transmit Originate  
2225 Hz Mark, 2025 Hz Space for  
Receive Originate  
2225 Hz Mark, 2025 Hz Space for  
Transmit Answer  
1270 Hz Mark, 1070 Hz Space for  
Receive Answer  
Carrier Frequencies  
V.21  
980 Hz Mark, 1180 Hz Space  
forTransmit Originate  
1650 Hz Mark, 1850 Hz Space for  
Transmit Answer  
1650 Hz Mark, 1850 Hz Space for  
Receive Originate  
980 Hz Mark, 1180 Hz Space for  
Receive Answer  
68  
 
Appendix A - Technical Specifications  
V.23  
390 Hz Mark, 450 Hz Space for  
Transmit Originate  
1300 Hz Mark, 2100 Hz Space for  
Transmit Answer  
1300 Hz Mark, 2100 Hz Space for  
Receive Originate  
390 Hz Mark, 450 Hz Space for  
Receive Answer  
Transmit Level  
-10dBm (dial-up)  
Frequency Stability  
Receiver Sensitivity  
±0.01%  
-43 dBm under worst case conditions  
43 dB  
AGC Dynamic  
Range  
Serial Interface  
Bus Type  
EIA RS232C/ITU V.24 Equivalent  
IBM PC Standard ISA or EISA  
Berg Jumpers  
Select COM1, COM2, COM3 or COM4  
communications port option  
Berg Jumpers  
Connectors  
Select IRQs 2, 3 ,4, 5 and 7 option  
Two RJ11C connections on modem  
interface (one for PSTN connection and  
one for manual dialing and answering  
via telephone device)  
Diagnostics  
Local Analog Loop, Local Digital Loop,  
Remote Digital Loop.  
Operating  
0° to 50° C (32° to 120° F)  
Temperature  
Power Consumption  
Dimensions  
1.2 Watts  
5.2"L x 3.0"W x .062"D  
13.2 cm x 7.62 cm x .165 cm  
Weight  
4.3 oz.  
122 grams  
Warranty  
10 Years  
 
69  
MT2834ZPX Owner's Manual  
Appendix B - Tone Dial Frequencies  
Hz  
Digits  
697  
770  
852  
941  
1
4
7
2
5
8
3
6
9
A
B
C
0
#
D
*
Hz 1209  
1336  
1477  
1633  
The tone-dialing method combines two frequencies for each of the  
twelve digits found on a Touch Tone dial pad. This method is referred  
to as Dual-Tone Multi-Frequency (DTMF) dialing. The four horizontal  
rows on a Touch-Tone keypad use the four low frequencies (697, 770,  
852, 941 Hz), while the three vertical columns use the three high  
frequencies (1209, 1336, 1477 Hz). The generally accepted tone  
frequency tolerance is +0.02%.  
For example, the digit 4 would be dialed by combining two tone  
frequencies. It would use the frequency 770 Hz from the second row,  
and the frequency 1209 Hz from the first column. In another example,  
the digit 9 would be dialed with the tone frequencies of 852 Hz and  
1477 Hz.  
The extended DTMF characters (A, B, C, D) are the high-end  
frequencies (1633 Hz) defined on some telephone sets with a fourth  
vertical column of buttons. This fourth column provides for extended  
PBX control functions; the actual functions provided are dependent on  
the PBX manaufacturer's implementation and feature set.  
70  
 
Appendix C - FCC and Canadian Regulations  
Appendix C - FCC and Canadian Regulations  
FCC Regulations for Telephone Line Interconnection  
1. This equipment complies with Part 68 of the Federal  
Communications Commission (FCC) rules. On the outside surface  
of this equipment is a label that contains, among other  
information, the FCC registration number and ringer equivalence  
number (REN). If requested, this information must be provided to  
the telephone company.  
2. As indicated below, the suitable jack (Universal Service Order  
Code connecting arrangement) for this equipment is shown. If  
applicable, the facility interface codes (FIC) and service order  
codes (SOC) are shown.  
An FCC-compliant telephone cord and modular plug is provided  
with this equipment. This equipment is designed to be connected  
to the telephone network or premises wiring using a compatible  
modular jack which is Part 68 compliant. See installation  
instructions for details.  
3. The ringer equivalence number (REN) is used to determine the  
quantity of devices which may be connected to the telephone line.  
Excessive REN’s on the telephone line may result in the devices  
not ringing in response to an incoming call. In most, but not all  
areas, the sum of the REN’s should not exceed five (5.0). To be  
certain of the number of devices that may be connected to the  
line, as determined by the total REN’s, contact the telephone  
company to determine the maximum REN for the calling area.  
4. If this equipment causes harm to the telephone network, the  
telephone company will notify you in advance that temporary  
discontinuance of service may be required. But if advance notice  
isn’t practical, the telephone company will notify the customer as  
soon as possible. Also, you will be advised of your right to file a  
complaint with the FCC if you believe it is necessary.  
5. The telephone company may make changes in its facilities,  
equipment, operations, or procedures that could affect the  
operation of the equipment. If this happens, the telephone  
company will provide advance notice in order for you to make  
necessary modifications in order to maintain uninterrupted  
service.  
 
71  
MT2834ZPX Owner's Manual  
6. If trouble is experienced with this equipment (the model of which  
is indicated below) please contact Multi-Tech Systems, Inc. at the  
address shown below for details of how to have repairs made. If  
the equipment is causing harm to the telephone network, the  
telephone company may request you remove the equipment from  
the network until the problem is resolved.  
7. No repairs are to be made by you. Repairs are to be made only by  
Multi-Tech Systems or its licensees. Unauthorized repairs void  
registration and warranty.  
8. This equipment cannot be used on public coin service provided by  
the telephone company. Connection to Party Line Service is  
subject to state tariffs. (Contact the state public utility commission,  
public service commission or corporation commission for  
information.)  
9. If so required, this equipment is hearing-aid compatible.  
Manufacturer:  
Model Number:  
Multi-Tech Systems, Inc.  
MT2834ZPX  
FCC Registration #:  
Ringer Equivalence:  
Modular Jack (USOC)  
Service Center in USA:  
AU7USA-20673-MM-E  
0.3B  
RJ11C or RJ11W (single line)  
Multi-Tech Systems Inc.  
2205 Woodale Drive  
Mounds View, MN 55112  
Voice (612) 785-3500/  
FAX (612) 785-9874  
72  
 
Appendix C - FCC and Canadian Regulations  
NOTE: This equipment has been tested and found to comply with the  
limits for a Class B digital device, pursuant to Part 15 of the FCC  
Rules. These limits are designed to provide reasonable protection  
against harmful interference when the equipment is operated in a  
residential installation. This equipment generates, uses and can  
radiate radio frequency energy, and if not installed and used in  
accordance with the instruction manual, may cause harmful  
interference to radio communications. However, there is no guarantee  
that interference will not occur in a particular installation. If this  
equipment does cause harmful interference to radio or television  
reception, which can be determined by turning the equipment off and  
on, the user is encouraged to try to correct the interference by one or  
more of the following measures:  
Reorient or relocate the receiving antenna.  
Increase the separation between the equipment and receiver.  
Connect the equipment into an outlet on a circuit different from that of  
which the receiver is connected.  
Consult the dealer or an experienced radio/TV technician for help.  
WARNING: Changes or modifications to this unit not expressly  
approved by the party responsible for compliance could void the user’s  
authority to operate this equipment.  
The Telephone Consumer Protection Act of 1991 makes it unlawful for  
any person to use a computer or other electronic device to send any  
message via a telephone fax machine unless such message clearly  
contains in a margin at the top or bottom of each page or the first page  
of the transmission, the date and time it is sent and an identification of  
the business or other entity, or other individual sending the message  
and the telephone number of the sending machine or such business,  
other entity, or individual. See the cover page of your fax software  
manual for setup details.  
This device complies with Part 15 of the FCC rules. Operation is  
subject to the following conditions: (1) This device may not cause  
harmful interference, and (2) this device must accept any interference  
received, including interference that may cause undesired operation.  
 
73  
MT2834ZPX Owner's Manual  
Canadian Limitations Notice  
Notice: The ringer equivalence number (REN) assigned to each  
terminal device provides an indication of the maximum number of  
terminals allowed to be connected to a telephone interface. The  
termination of a interface may consist of any combination of devices  
subject only to the requirement that the sum of the ringer equivalence  
numbers of all the devices does not exceed 5.  
Notice: The Industry Canada label identifies certificated equipment.  
This certification means that the equipment meets certain  
telecommunications network protective, operational and safety  
requirements. The Industry Canada does not guarantee the equipment  
will operate to the user’s satisfaction.  
Before installing this equipment, users should ensure that it is  
permissible to be connected to the facilities of the local  
telecommunications company. The equipment must also be installed  
using an acceptable method of connection. The customer should be  
aware that compliance with the above conditions may not prevent  
degradation of service in some situations.  
Repairs to certified equipment should be made by an authorized  
Canadian maintenance facility designated by the supplier. Any repairs  
or alterations made by the user to this equipment, or equipment  
malfunctions, may give the telecommunications company cause to  
request the user to disconnect the equipment.  
Users should ensure for their own protection that the electrical ground  
connections of the power utility, telephone lines and internal metallic  
water pipe system, if present, are connected together. This precaution  
may be particularly important in rural areas.  
Caution: Users should not attempt to make such connections  
themselves, but should contact the appropriate electric inspection  
authority, or electrician, as appropriate.  
74  
 
Index  
Index  
Symbols  
&E0 .......................................................................................... 20  
&E1 .......................................................................................... 20  
&E14 ........................................................................................ 19  
10/11 bit mode selection .......................................................... 27  
16550 UART and Windows 3.1 ................................................ 20  
A
Abort Timer  
S7 ......................................................................................... 41  
About CompuServe ................................................................. 65  
About the Multi-Tech BBS ........................................................ 63  
AGC Dynamic Range .............................................................. 69  
Alternate COM Port/IRQ Settings .............................................11  
ASCII code .............................................................................. 16  
AT command set ...................................................................... 32  
AT&T's "call card" tones .......................................................... 24  
Auto-answer ......................................................................16, 17  
B
Backspace Character .............................................................. 41  
Baud rate ................................................................................. 17  
Bell/V.21 answer tone selection ............................................... 25  
Buffer Length of Command Mode. ........................................... 44  
S34 ....................................................................................... 44  
Bulletin Board Systems ....................................... 15, 18, 19, 21  
Bus Type .................................................................................. 69  
Bypass V.32terbo handshaking process .................................. 35  
C
Call waiting .............................................................................. 53  
Calling tones ............................................................................ 34  
Calling Tones enabled/disabled ............................................... 34  
Canadian Limitations Notice .................................................... 73  
 
75  
MT2834ZPX Owner's Manual  
Cannot Make a Connection ..................................................... 51  
Carrier Detect .......................................................................... 26  
Carrier Detect Response Time ................................................ 42  
Carrier Frequencies (Data) ...................................................... 68  
Carrier Loss Disconnect Delay Time ....................................... 42  
Changing Break Time .............................................................. 43  
Clear to Send ........................................................................... 32  
Cleardown on disconnect ........................................................ 26  
COM ports .........................................................................17, 21  
COMM.DRV .......................................................................21, 54  
Command Buffer ...................................................................... 67  
Command mode characters control ......................................... 27  
Command string ...................................................................... 16  
Commands ................................................................. 15, 19, 20  
Non-Error Correction mode .................................................. 20  
Reliable mode ...................................................................... 20  
Compatibility ............................................................................ 66  
CompuServe ............................................................... 20, 21, 65  
CompuServe/Internet .............................................................. 65  
Configuration Parameters ........................................................ 17  
Connectors .............................................................................. 69  
Continuous redial ..................................................................... 24  
CTS flow control ...................................................................... 28  
CTS follows RTS ..................................................................... 33  
CYBERC.ZIP ........................................................................... 21  
D
Data Compression .............................................................19, 66  
Enabled/disabled .................................................................. 28  
Data Format ............................................................................. 66  
Data Rates ............................................................................... 66  
Data Rates (fax) ...................................................................... 66  
Data Rates (modem) ............................................................... 66  
Data Set Ready ....................................................................... 34  
Datacomm software ............................... 15, 16, 17, 18, 19, 49  
Configuration ........................................................... 15, 17, 18  
Detecting DTMF tones ............................................................. 27  
Diagnostics .............................................................................. 69  
76  
 
Index  
Dialing a stored telephone ....................................................... 31  
Dimensions .............................................................................. 69  
DSR follows CD ....................................................................... 33  
DTR Control ............................................................................. 26  
DTR Dialing ............................................................................. 26  
DTR Dropout Time ................................................................... 43  
E
Enq/Ack pacing ........................................................................ 28  
Error Correction ....................................................................... 66  
Error correction ........................................................................ 20  
Escape Code Character .......................................................... 40  
Escape modes selection .......................................................... 28  
Exit Command Mode ............................................................... 31  
Extended DTMF characters ..................................................... 70  
F
Factory default values ............................................................. 28  
Fax Carrier Frequencies .......................................................... 67  
Fax Modulations ...................................................................... 67  
Fax-Back Service .................................................................... 65  
FCC Regulations ..................................................................... 71  
Features .................................................................................... 5  
Flash On-Hook ........................................................................ 37  
Flow Control ...................................................................... 66, 54  
Flow control selection .............................................................. 28  
Frequency Stability .................................................................. 69  
G
Garbage Characters ................................................................ 55  
Guard tones ............................................................................. 29  
I
In-band Escape Sequence ...................................................... 37  
Inactivity Timer ......................................................................... 44  
Initialization strings .............................................. 15, 19, 49, 51  
PC-compatible ...................................................................... 16  
 
77  
MT2834ZPX Owner's Manual  
Intelligent Features .................................................................. 67  
Interface ................................................................................... 69  
Internet .................................................................................... 65  
L
L8 .......................................................................................54, 55  
Limited Warranty ...................................................................... 60  
Line Feed Character ................................................................ 41  
S4 ......................................................................................... 41  
Line Probe ............................................................................... 27  
List operating parameters ........................................................ 30  
Login Password ....................................................................... 39  
Long space “break ................................................................... 36  
Loopback Test Enabled ........................................................... 35  
M
Maximum transmit block size selection ................................... 25  
MNP 5 ................................................................................19, 54  
Mode of Operation ................................................................... 66  
Model Numbers ....................................................................... 66  
Modem AT Commands ............................................................ 23  
Modem baud selection ............................................................. 30  
Modem Cannot Connect When Answering .............................. 54  
Modem Disconnects While Online ........................................... 53  
Modem Does Not Respond to Commands .............................. 49  
Modem Features ....................................................................... 5  
Modem ID ................................................................................ 29  
Modem Initialization Setup ....................................................... 16  
Modular phone jack ................................................................. 12  
Modulation ............................................................................... 67  
MT2834BC Printed Circuit Board ............................................11  
Multi-Tech BBS ........................................................................ 63  
Multi-Tech command set .......................................................... 32  
Multi-Tech responses ............................................................... 46  
"Multi-Tech" Result Codes ....................................................... 46  
MultiExpress for Windows .................................................52, 53  
78  
 
Index  
N
Negotiate V.42 Mode ............................................................... 30  
Noise Information .................................................................... 30  
Non-volatile RAM ..................................................................... 35  
Number Linking ....................................................................... 31  
Number of Rings Until Modem Answers .................................. 45  
S0 ......................................................................................... 40  
O
Off Hook control ....................................................................... 29  
Operating Temperature ............................................................ 69  
Out-of-band Escape Sequence ............................................... 37  
P
Pacing ...................................................................................... 28  
Parameters ........................................................................15, 17  
Changing defaults ................................................................ 17  
Parity ....................................................................................... 15  
Pause during dialing ................................................................ 36  
Pause Time for Comma ........................................................... 42  
PBX/CBX Disconnect Drop Time for DSR/CTS/CD ................ 43  
PC Initialization Strings ............................................................ 16  
Power Consumption ................................................................ 69  
Product Description ................................................................... 6  
Program V34 Connect Speeds ................................................ 45  
Protocols ............................................................................19, 54  
Pulse ratio ................................................................................ 32  
Pulse-dial ................................................................................. 31  
R
Read value of Register ............................................................ 33  
Receiver Sensitivity ................................................................. 69  
Remote Configuration Escape Character ................................ 43  
Remote Configuration Operation Procedures ....................38, 39  
Remote Digital Loopback ......................................................... 34  
Remote System Configuration ................................................. 18  
Repeat last command .............................................................. 24  
 
79  
MT2834ZPX Owner's Manual  
Rreset default values .............................................................. 36  
Result Codes .....................................................................32, 36  
Result codes ......................................................................16, 51  
Result Codes Terse/Verbose selection .................................... 35  
Retransmit ............................................................................... 32  
Return Character ..................................................................... 41  
Return character ...................................................................... 16  
Return to Command Mode after dialing ................................... 37  
Rings Which Have Occurred  
S1 ......................................................................................... 40  
S
S-Registers  
S3 ......................................................................................... 16  
Serial port ............................................................ 17, 20, 21, 50  
Serial port commands .............................................................. 33  
Sessions .................................................................................. 15  
Set-up Password ..................................................................... 39  
Sets value of Register ............................................................. 33  
Signal Strength Information ..................................................... 30  
Signal to Noise Ratio Information ........................................... 30  
SIT files .................................................................................... 19  
Software User License Agreement .......................................... 61  
Speed Conversion ................................................................... 66  
Speed conversion .................................................................... 25  
Standard AT command set responses ..................................... 46  
"Standard AT" Result Codes .................................................... 47  
T
Tech Support ........................................................................... 61  
Technical Specifications .......................................................... 66  
Telephone line .......................................................................... 51  
Terminal Emulation Setup ........................................................ 18  
Terminal mode ......................................................................... 49  
Terse/Verbose .......................................................................... 46  
Testing ..................................................................................... 51  
Time Elapse for Escape Sequence ......................................... 44  
Time for Carrier (Abort Timer) .................................................. 41  
Tone Dialing: Tone Spacing and Duration ................................ 42  
80  
 
Index  
Transmission speed ................................................................. 17  
Transmit buffer size ................................................................. 25  
Transmit Level ......................................................................... 69  
Trellis Coded Modulation selection .......................................... 34  
U
UARTs ........................................................................ 20, 21, 54  
16450 ................................................................................... 20  
16550 ...................................................................... 20, 21, 54  
8250A ................................................................................... 20  
Buffers ............................................................................20, 21  
V
V.32terbo handshaking process .............................................. 35  
V.34 Line Probe ....................................................................... 27  
V.42 ......................................................................................... 20  
V.42bis ........................................................................ 17, 19, 20  
W
Wait for ringback ...................................................................... 37  
Wait Time for Dial Tone ............................................................ 41  
Warranty .................................................................................. 60  
Weight ..................................................................................... 69  
Windows 3.1 ............................................................... 20, 21, 54  
Serial port driver ............................................................. 21, 54  
Windows 95 Autodetect (I9) ..................................................... 30  
Windows 95 HyperTerminal ..................................................... 53  
X
Xmodem .................................................................................. 54  
Xon/Xoff flow control ............................................................... 28  
Y
Ymodem/G .............................................................................. 54  
Z
ZIP files .................................................................................... 19  
Zmodem .................................................................................. 54  
 
81  

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