Multitech MultiModem MT5600ZDXV Owner's Manual

Model MT5600ZDXV

K56flex
Data/Fax Modem with AT#V
Voice Command Set Support

Owner's Manual

2

Model MT5600ZDXV

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.

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.

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Owner's Manual

Owner’s Manual

82069501 Revision B

Model # MT5600ZDXV

This publication may not be reproduced, in whole or in part, without
prior expressed written permission from Multi-Tech Systems, Inc. All
rights reserved.

Copyright © 1998, by Multi-Tech Systems, Inc.

Multi-Tech Systems, Inc. makes no representations or warranties with
respect to the contents hereof and specifically disclaims any implied
warranties of merchantability or fitness for any particular purpose.
Furthermore, Multi-Tech Systems, Inc. reserves the right to revise this
publication and to make changes from time to time in the content
hereof without obligation of Multi-Tech Systems, Inc. to notify any
person or organization of such revisions or changes.

Revision Description

B Revised AT commands and S-Registers; added information

8/25/98 on V.90 and the SPKR and LINE IN jacks.

MultiModemZDXV, Multi-Tech, and the Multi-Tech logo are trademarks
of Multi-Tech Systems, Inc.
K56flex is a registered trademark of Rockwell and Lucent Technologies
Corp. ©Rockwell Semiconductor Systems, Inc. 1997
All Rights Reserved. Reproduced by Permission.
All brand and product names mentioned in this publication are trade­marks or registered trademarks of their respective companies.

Multi-Tech Systems, Inc.

2205 Woodale Drive

Mounds View, Minnesota 55112 U.S.A.

[phone] or [phone]

U. S. FAX [phone]

Fax-Back Service 612-717-5888

Technical Support [phone]

BBS [phone] or [phone]

Internet Address: http://www.multitech.com

Technical Writer: [e-mail]

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Model MT5600ZDXV

TABLE OF CONTENTS

CHAPTER 1 -- INTRODUCTION AND DESCRIPTION

1.1 Introduction.................................................................................. 1-1

1.2 Product Description...................................................................... 1-1

1.3 Software Considerations............................................................... 1-4

1.3.1 What is in Your Modem Package? .................................... 1-4

1.4 How To Use This Manual ............................................................. 1-5

CHAPTER 2 -- INSTALLATION AND CONNECTION

2. 1 Installation .................................................................................... 2-1

2.1.1 Computer............................................................................ 2-1

2.1.2 Serial Cable......................................................................... 2-1

2.1.3 Telephone Line................................................................... 2-2

2.1.4 Safety Warnings................................................................. 2-2

2.1.5 Communications Software................................................. 2-2

2.2 Installation Process....................................................................... 2-3

2.2.1 SoundCard Considerations................................................. 2-5

2.3 LED Indicators............................................................................... 2-6

2.4 Is Your MT5600ZDXV Ready for Use? ......................................... 2-9

2.5 Operating Your MT5600ZDXV...................................................... 2-9

2.5.1 Simple Operations ........................................................... 2-10

2.6 Software Configuration .............................................................. 2-11

2.6.1 Hardware/Software Confirmation ................................... 2-12

2.7 Troubleshooting.......................................................................... 2-13

2.7.1 None of the LEDs Light When the Modem Is On ........... 2-13

2.7.2 The Modem Does Not Respond to Commands ............... 2-14

2.7.3 The Modem Dials But Does Not Make a Connection ...... 2-16

2.7.4 The Modem Disconnects While Online ........................... 2-19

2.7.5 The Modem Cannot Connect When Answering ............. 2-20

2.7.6 Slow File Transfer ............................................................ 2-20

2.7.7 Losing Data ...................................................................... 2-20

2.7.8 Garbage Characters on the Monitor ................................ 2-21

CHAPTER 3 -- AT COMMANDS, S-REGISTERS

& RE-

SULT CODES

3.1 AT Commands............................................................................... 3-1

3.2 S-Registers................................................................................... 3-23

3.2.1 Result Codes..................................................................... 3-39

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Owner's Manual

CHAPTER 4 – TESTING YOUR MT5600ZDXV

4 .1 Local Analog Loopback Test/V.54 Loop 3....................................... 4- 1

4.2 Digital Loopback Test/V.54 Loop 2 (Local/Manual) ........................ 4-2

4.3 Digital Loopback Test/V.54 Loop 2 (Remote/Automatic) ............... 4-4

CHAPTER 5 – SERVICE, WARRANTY & TECH

SUPPORT/BBS

5.1 Introduction ...................................................................................... 5-1

5.2 Limited Warranty .............................................................................. 5 -1

5 .3 Tech Support .................................................................................... 5-2

5.3.1 Recording Modem Information ............................................... 5-2

5.3.2 Service..................................................................................... 5-3

5 . 4 About the Multi-Tech BBS ................................................................ 5-4

5.4.1 How to Use the Multi-Tech BBS ............................................. 5-4

5.4.2 Using Flash to Upgrade Modem Firmware .............................. 5 - 6

5.5 About CompuServe/Internet ............................................................. 5-9

5.6 About the Multi-Tech Fax-Back Service ............................................ 5-9

APPENDICES

Appendix A - Technical Specifications A-1
Appendix B - Tone Dial Frequencies B-1
Appendix C - FCC, Canadian and BABT Regulations C - 1
Appendix D - V.90 Information D-1

INDEX

FIGURES

Figure No.Title Page No.

2-1 Serial Connectors 2-1
2-2 MT5600ZDXV Connections 2-3

2-2

a

MT5600ZDXV Connections 2-4
2-3 MT5600ZDXV SoundCard Connections 2-5
2-4 MT5600ZDXV Front Panel 2-6
2-5 MT5600ZDXV Front Panel LEDs 2-7
2-6 MT5600ZDXV Initialization Setup 2-11
4-1 Local Analog Loopback Test 4-1
4-2 Digital Loopback Test (Local/Manual) 4-3
4-3 Digital Loopback Test (Remote/Automatic) 4-4

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Model MT5600ZDXV

TABLES

Table No. Title Page No.

2-1 Setting Up Protocols via AT Command Strings 2-17
3-1 Subparameter Definitions 3-18
3-2 Distinctive Ring Types 3-19
3-3 V.42 Negotiation Action 3-36
3-4 Result Codes 3-39

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Owner's Manual

1.1 Introduction

Welcome to the world of data communications. You have acquired one of
the finest intelligent data, fax, answering machine and personal voice mail
capable modems available today, model MT5600ZDXV, from Multi-Tech
Systems. This Owner’s Manual will help you install, configure, test and use
your MT5600ZDXV modem.

1.2 Product Description

Your MT5600ZDXV incorporates both V.90 and K56flex modem
technologies,which allows Internet connections at data rates up to 56K bps
over standard telephone lines. The V.90 and K56flex technology is able to
propel data downstream from the Internet to your computer at speeds of up
to 56K bps because data is digitally encoded instead of modulated. Upstream
transmission, mostly keystroke and mouse commands from your computer to
the central site, continue to flow at the conventional data rate of 33.6K bps.

Your MT5600ZDXV offers interactive automatic dialing, as well as command
mode option configuration. You may store four command line/telephone
numbers, of up to 40 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).

* Though this modem is capable of 56K bps download performance, line
impairments, public telephone infrastructure and other external technological
factors currently prevent maximum 56K bps connections.

The MT5600ZDXV is a desktop fax/modem for compatible Personal Comput­ers that also provides support for answering machine and voice mail
capabilities. The MT5600ZDXV 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
and/or an attached telephone device is made by RJ11 modular type
connectors; the PC connection is made via an RS232C/V.24 serial cable
receptacle, and low voltage DC power is supplied to the MT5600ZDXV
through a modular power supply connection included with the modem. All
of these connections are made at the back of the MT5600ZDXV.
The “SPKR or LINE OUT” and “MIC IN” jacks are both located on the side of

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Model MT5600ZDXV

the MT5600ZDXV. Hardware installation procedures are described in
Chapter 2.

General features include:
4 Compliance with major ITU-T, TIA, and EIA international standards to

ensure compatibility with other modems.

4 Distinguishes data, fax, or voice calls using DTMF and tone detection with

software packages supporting these features.

4 Caller ID to identify your caller’s phone number (available on U.S.

products).

Data

4 Supports the V.90 and K56flexTM standards for data transmission at speeds

up to 56Kbps, while maintaining compatibility with lower-speed modems.
Note: the V.90 and K56flex standards transfer data asymmetrically - client

downloads at speeds up to 56K bps, client uploads at speeds up to 33.6K
bps.

4 Supports the enhanced ITU-T V.34 standard, with data transmission

speeds to 33.6K bps, while also maintaining compatibility with lower­speed modems.

4 Supports V.90 and K56flex speeds plus 33.6K, 31.2K, 28.8K, 26.4K, 24K,

21.6K, 19.2K, 16.8K, 14.4K, 12K, 9.6K, 7.2K, 4.8K, 2.4K, 1.2K, and 0­300 bps.

4 Automatic fallback to slower speeds in noisy line conditions, and fall-

forward to faster speeds as conditions improve.

4 ITU V.42 LAP-M and MNP Class 3 and 4 error correction.
4 ITU V.42bis (4-to-1) and MNP 5 (2-to-1) data compression.
4 Automatic disabling of compression when transferring already-com-

pressed files.

4 Autodial, redial, pulse (rotary) and touch-tone dial.
4 Dial tone and busy signal detection for reliable call-progress detection.
4 Compatibility with the standard AT command set used by most commu-

nication programs.

4 MNP10 and MNP10EC

TM

Enhanced Cellular Performance (error correction).

4 H.324 compliant (videophone ready).
4 Distinctive ring support to route voice, data, or fax calls on a single phone

line.

4 Plug and Play (

PnP

) serial support.

4 FlashROM upgradable.

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Owner's Manual

Fax

4 Supports V.17, Class 1/Group 3 fax communication standards, allowing

it to communicate with other fax modems as well as with fax machines.

4 Sends and receives faxes from your computer at 14,400 bps, 9600 bps,

7200 bps, 4800 bps, 2400 bps, or 300 bps.

Voice

4 Full-duplex speakerphone support with adjustable speaker volume con-

trol. Can record and play back answering machine messages using
optional microphone and speaker.

4 Remote/local telephone answering machine (TAM) capabilities include

voice mail control, record/playback, and call screening.

4 Supports AT#V voice commands.

* For more information on the #V commands supported by the MT5600ZDXV, refer

to the Voice #V Commands Developer's Kit . This document is available
upon request, and at

www.multitech.com/support/manuals.asp

.

1.3 Software Considerations

You will need data communications (datacomm), fax communications
software and an appropriate application software package to access the
Personal Voice-Mail features of the MT5600ZDXV. You must have Microsoft
Windows 3.1 or later to run these programs. With the appropriate application
software you can use your MT5600ZDXV to:

• speed dial

• mute a phone call

• place a call on hold

• forward or transfer a call

• three-way or conference call

• fax from any Windows’ application

• record telephone conversations

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Model MT5600ZDXV

1.3.1 What Is in Your Modem Package?

Your MultiModemZDXV has several components. Make sure you have them all
before installing your modem. Your package should include:

 MultiModemZDXV modem
 DC power supply
 One set of four plastic feet
 Two sets of Velcro fasteners
 Telephone cord
 MultiModemZDXV Owner’s Manual (this manual)
 Data Communications Software
 One Set-Up diskette
 Brochure with warranty registration card

If any of these items are missing, please contact Multi-Tech Systems or your
dealer/distributor.

1.4 How to Use This Manual

This manual is divided into five chapters and three 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

Details are given, supported by illustrations as a guide for installing your
MT5600ZDXV to the point of operation. There is also a Troubleshooting
section in the event your MT5600ZDXV is not operating properly.

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Owner's Manual

Chapter 3 - AT Commands, S-Registers and Result Codes

Chapter 3 documents default and option ATcommands, S-Registers and
Result Codes supported by the MT5600ZDXV.

Chapter 4 - Testing Your Modem

Chapter 4 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 5 - Service, Warranty & Tech Support/BBS

Chapter 5 provides instructions for getting modems serviced at the factory,
statements on your ten-year warranty, the procedure for downloading
firmware upgrades via FlashROM, information about our user Bulletin Board
Service (

BBS

) and receiving technical support via the CompuServe and

Internet forums.

Appendixes

Appendix A - Technical Specifications
Appendix B - Tone Dial Frequencies
Appendix C - FCC, Canadian and BABT Regulations
Appendix D - V.90 Information

2.1 Installation

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Model MT5600ZDXV

In addition to the contents of the MT5600ZDXV package, you will need
the following equipment.

2.1.1 Computer

The MT5600ZDXV can be connected to any computer with an RS-232
serial port.

Note that your computer system should have a processor speed
of at least 75 MHz in order to take full advantage of the telephony features
of this product.

2.1.2 Serial Cable

You must provide a serial cable to connect the MT5600ZDXV to your computer.
Serial cables are available at computer stores and many office supply stores.
The cable must have a DB-25P connector at the modem end. For IBM and
compatible computers, the other end may have a DB-25P connector or a
DB-9S connector, depending on your particular computer and whether you are
using the COM1 or the COM2 serial port. The FCC requires cables to be shielded.

DB-25

DB-9

Figure 2-1. Serial Connectors

2.1.3 Telephone Line

You must have a telephone line with a conveniently located connector
(jack) to accept the cable that comes with the MT5600ZDXV. If you do not
have a telephone jack near your computer, you should install an extension
before proceeding.
In North America, telephone extension kits and accessories are available at
electronics stores and wherever telephones are sold. You may also hire an
independent contractor or your local telephone company to do the work.
If you want to add a line for your MT5600ZDXV fax modem, you must
contact your telephone company.

2.1.4 Safety Warnings

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Owner's Manual

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.Never touch uninsulated telephone wires or terminals unless the telephone
line has been disconnected at the network interface.

4 .Use caution when installing or modifying telephone lines.
5 . Avoid using a telephone (other than a cordless type) during an electrical

storm. There may be a remote risk of electrical shock from lightning.

6 . Do not use the telephone to report a gas leak in the vicinity of the leak.

2.1.5 Communications Software

You will need data communications (datacomm), fax communications
software and an appropriate application software package to access the
Personal Voice-Mail features of the MT5600ZDXV. You must have Microsoft
Windows 3.1 or later to run these programs. The MT5600ZDXV is also
compatible with datacomm and fax programs you may already own.

2.2 Installation Process

The installation of the MT5600ZDXV consists of making the physical connections
necessary to render the modem functional with your computer. This includes
making the proper serial, phone line, and power connections.

RS232

PHONE LINE

RJ11/Phone Connection

RJ11/PSTN Connection

Power Connector
(to Transformer)

DB25 to Computer

POWER

Figure 2-2. MT5600ZDXV Connections

To install your MT5600ZDXV:

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Model MT5600ZDXV

1.Attach MT5600ZDXV to dial-up phone lines using the RJ11 telephone cord.
This is accomplished by plugging one end of the cable provided with the
MT5600ZDXV into the telephone jack in your home or office; and plugging
the other end into the LINE jack on the MT5600ZDXV.

The LINE jack is not interchangeable with the PHONE jack on the
MT5600ZDXV. Do not plug the telephone into the LINE jack or the line
cable into the PHONE jack.

2.Attach your MT5600ZDXV to your PC or terminal with an RS232 (or V.24)
cable (see Figure 2-1). Be sure to tighten the mounting screws on the DB
connectors.

3 .Connect your telephone set to phone jack via RJ11 cable.

4.Attach your MT5600ZDXV to the AC Power transformer and plugging the
AC connector into a live AC outlet.

5.Turn on power by flipping the

"ON/OFF"

switch on the side of the

MT5600ZDXV to the

"ON"

position.
Use only the power supply provided with the MT5600ZDXV. Use of any
other power supply will void the warranty and could damage the modem.

6.Make sure modem and computer/terminal serial port baud rates are
adjusted. (Note that several programs can check this for you. If you have
MS-DOS 5.0 or higher, a program called MSD.EXE [Microsoft Diagnostics]
is in your DOS directory. Typing MSD at the DOS prompt brings up a screen
that provides a variety of information about your computer. Select COM
ports and it lists information about your com port, e.g., UART Type,
Address, and IRQ, to name a few. Once you know your serial port's UART
type, you can set your communications's software appropriately.)

7 . Proceed to Chapter 3 of this manual, or to your data communications

software manual.

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Owner's Manual

✳

#

Figure 2-2a. MT5600ZDXV Connections

2.2.1 SoundCard Considerations

If you want speakerphone functions along with the ability to record sound
or .WAV files through the sound card at the same time, you need:

• two stereo PC microphones

• one stereo male-to-male patch cord

• one sound card and optional speakers

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Model MT5600ZDXV

S

P

K

RM

IC

O

F

F

O

N

"SPKR" or "LINE
OUT" to connect
to an optional
Speaker--connect
to the "LINE IN"
of a 3rd Party
Sound Card.

"MIC IN" Jack to
connect to an
optional
Microphone.

Power Switch
ON/OFF

Figure 2-3. MT5600ZDXV SoundCard Connections

To connect to a 3rd party sound card, perform the following steps:

1. Obtain a stereo male-to-male patch cord (can be purchased at a local

PC retail store).

2. Place one end of a stereo male-to-male patch cord into the “SPKR or

LINE OUT” jack of the ZDXV and the other end into the “LINE IN “ jack of
the sound card. This lets you to hear the activity of the modem whether
it is originating or answering a call or playing a recorded message using
the bundled Trio software.

3. Place the two stereo microphones (do not use mono microphones) far

enough apart from each other to eliminate feedback (e.g., one on each
side of the monitor). Feedback will only occur if the microphones are too
close to each other. Make sure speakers are amplified with power source
being either a battery or AC outlet.

4. Place the microphone and speakers far enough apart from each other

to eliminate feedback. Plug the connector of both microphones into the
“MIC IN” jack of both the SoundCard and the ZDXV.

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Owner's Manual

2.3 LED Indicators

The MT5600ZDXV has ten LED indicators (Figure 2-4) to report MT5600ZDXV
status (such as verifying proper installation) and line activity (such as
monitoring the status of a connection).

K56flex

™

Voice Mail Modem

Figure 2-4. MT5600ZDXV Front Panel

TD

Transmit Data. The TD LED flashes when data is being transmitted (on for a
space, off for a mark). Signals on this circuit are generated by the terminal
and transferred to the transmitter of the MT5600ZDXV. The transmitting
terminal should hold this line in the marking state when no data is being
transmitted, including intervals between characters or words. The TRANSMIT
(TD) LED indicates the status of this circuit.

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Model MT5600ZDXV

RD

Receive Data. The RD LED flashes when data is being received (on for a space,

off for a mark). Data signals received from the remote MT5600ZDXV are
presented on this line. When no carrier signal is being received (pin 8
negative), this line will be forced into a marking condition. The RECEIVE (RD)
LED indicates the status of this signal.

CD

Carrier Detect. This LED lights when a valid carrier signal from another modem
is detected.

56

56K. This LED is lit when connected to an ISP-type K56flex server. The actual
connection speed is contingent upon server capabilities and line conditions.

28

V.34. This LED is lit when the modem is connected in V.34 mode.

14

V.32

bis

. This LED is lit when the modem is connected in V.32

bis

mode. Note

that at speeds lower than a V.32

bis

connection, the MT5600ZDXV speed LEDs

remain unlit.

OH

Off Hook. The condition of Off Hook indicates to the central office that the

MT5600ZDXV wants the phone line to do something (i.e., dial or answer a
call). This LED is also lit when the MT5600ZDXV has achieved on-line status.

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Owner's Manual

TR

Terminal Ready. When TR is lit, the MT5600ZDXV can answer an incoming
call. This signal (TR or DTR) provides a means for the terminal or computer
to control the MT5600ZDXV's connection to the communications channel.
A high DTR signal is required by the MT5600ZDXV to be able to communicate.
The state of the TR LED matches that of the DTR circuit on pin 20 of the RS232/
V.24 interface.

EC

Error Correction. This LED is lit when the modem is set for V.42 error
correction, and flashes on and off when data compression is activated.

FX

Fax. This LED is lit when the modem is connected in Fax mode.

Figure 2-5. MT5600ZDXV Front Panel LEDs

2.4 Is Your MT5600ZDXV Ready for Use?

As soon as you have 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 the

AT&V<cr>

command. This
command lists how your modem is currently configured. If you come across
a setting you’re unsure of, refer to Chapter 3 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.

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Model MT5600ZDXV

2.5 Operating Your MT5600ZDXV

You control your MT5600ZDXV by issuing AT commands and setting
S-Registers. Right now your MT5600ZDXV 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 Chapter 3 for AT
Commands and S-Registers.)

In operating your MT5600ZDXV 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

.

2.5.1 Simple Operations

You can dial 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 ATH0<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.