Multitech MultiModem MTCBA-G-F4 User manual

MultiModem®GPRS
Wireless Modem
MTCBA-G-F4
User Guide

Copyright and Technical Support
2 Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide
MultiModem® GPRS User Guide
Wireless Modem
MTCBA-G-F4
S000443E, Revision E
Copyright
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 © 2013 by Multi-Tech Systems, Inc.
Multi-Tech Systems, Inc. makes no representation 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. Check Multi-Tech’s website for current versions of our product documentation.
Revision History
Revision
Date
Description
A
10/03/07
Initial Release
B
11/19/08
Remove fax requirements and minor editorial changes.
C
06/15/2011
Removed references to CDs
D
08/02/2012
Updated regulatory section.
E
12/16/2013
Added UL translations.
Trademarks and Logos
The Multi-Tech logo and MultiModem are registered trademarks of Multi-Tech Systems, Inc. Windows is a registered trademark
of Microsoft in the U.S. and other countries. Other trademarks and trade names mentioned in this publication belong to their
respective owners.
World Headquarters
Multi-Tech Systems, Inc.
2205 Woodale Drive
Mounds View, Minnesota 55112
Phone: [phone] or 800-328-9717
Fax: [phone]
Internet Address: http://www.multitech.com
Technical Support
Country
By Email
By Phone
Europe, Middle East, Africa
[email protected]
+(44) 118 959 7774
U.S., Canada, all others
[email protected]
[phone] or +[phone]
Warranty
Warranty information can be found at: http://www.multitech.com

Contents
Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide 3
Contents
Chapter 1 –Product Description and Specifications................................................................5
Product Description ................................................................................................................................... 5
Safety............................................................................................................................................................ 5
General...........................................................................................................................................................5
RF Safety.......................................................................................................................................................5
Vehicle Safety ...............................................................................................................................................6
Maintaining Your Modem.............................................................................................................................6
Your Responsibility.......................................................................................................................................7
Package Contents....................................................................................................................................... 7
General Specifications............................................................................................................................... 7
Functions –GSM/GPRS Modes................................................................................................................ 7
Electrical Specifications............................................................................................................................ 8
RF Specifications........................................................................................................................................ 8
Antenna Specifications.............................................................................................................................. 9
GSM/EGSM Antenna Requirements/Specifications................................................................................9
Antennas Available from Multi-Tech Systems, Inc..................................................................................9
PTCRB Requirements Note........................................................................................................................9
FCC Requirements Note.............................................................................................................................9
Interfaces.................................................................................................................................................... 10
LEDs.............................................................................................................................................................10
RS232 15-Pin Connector Pinout............................................................................................................. 10
AT Command Information....................................................................................................................... 10
Chapter 2 –Activation and Installation.....................................................................................11
Activating Your Wireless Account......................................................................................................... 11
Inserting the SIM Card into the Holder ................................................................................................. 11
Connecting the Antenna, Serial Cable, and Power............................................................................. 12
Connecting Two-Piece Transformer Power Supply (International).....................................................12
Connecting One-Piece Transformer Power Supply (North America) .................................................12
Connecting Optional Direct DC Power....................................................................................................12
Optional –Attaching the Modem to a Flat Surface............................................................................. 13
Installing the Modem Driver.................................................................................................................... 13
Before you Begin........................................................................................................................................13
Installing the MultiModem Driver on a PC Running Windows Vista/XP/2003...................................13
Verifying That Your Modem Has Been Installed Successfully.............................................................16

Contents
4 Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide
Chapter 3 –Using Your Wireless Modem.................................................................................17
Obtaining a Phone Number for the Wireless Modem......................................................................... 17
Checking Signal Strength and Network Registration ........................................................................ 17
Before You Begin........................................................................................................................................17
Downloading the AT reference guide from the Multi-Tech website ....................................................17
Verifying Signal Strength...........................................................................................................................17
Checking Network Registration and Roaming Status...........................................................................18
Checking the Modem’s Identity ................................................................................................................18
Establishing a Voice Call...........................................................................................................................18
Establishing a Circuit-Switched Data (CSD) Connection .....................................................................19
Answering a Circuit-Switched Data (CSD) Connection ........................................................................19
Using Short Message Services (SMS)....................................................................................................20
SMS Examples............................................................................................................................................21
Internet Access......................................................................................................................................... 23
Connecting to the GPRS Network for Internet Access .........................................................................23
Chapter 4 –Troubleshooting and Frequently Asked Questions ...........................................26
Troubleshooting Examples..................................................................................................................... 26
Situation A: The modem does not answer..............................................................................................26
Situation B: The modem always returns «No carrier» when trying to originate a call......................27
Frequently Asked Questions.................................................................................................................. 27
Appendix A –Cables...................................................................................................................30
Data Cable Diagram –No Voice ............................................................................................................. 30
Data Cable Diagram –with Voice........................................................................................................... 31
Fused DC Power Cable Dimensions.......................................................................................................31
Appendix B –Regulatory and Compliance Information .........................................................32
47 CFR Part 15 Regulation Class B Devices........................................................................................ 32
Industry Canada........................................................................................................................................ 32
Waste Electrical and Electronic Equipment (WEEE).......................................................................... 33
Instructions for Disposal of WEEE by Users in the European Union..................................................33
REACH Statement..................................................................................................................................... 34
Restriction of the Use of Hazardous Substances (RoHS)................................................................. 35
Information on HS/TS Substances According to Chinese Standards............................................. 36
Information on HS/TS Substances According to Chinese Standards (in Chinese)...................... 37

Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide 5
Chapter 1 –Product Description and
Specifications
Product Description
The Multi-Tech MultiModem® GPRS is an external data/fax/voice wireless modem. It also supports
mobile originated short message service (SMS) and mobile-terminated SMS. It offers standards-based
multi-band GPRS Class 10 performance. This ready-to-deploy, standalone modem allows developers to
add wireless communication to products with a minimum of development time and expense. The
MultiModem GRPS Wireless Modem is based on industry-standard open interfaces, is fully type
approved, and can be desktop or panel mounted.
Product codes include:
●NAM is the model for US and Canada
●GB/IE is the model for Great Britain and Ireland
●Euro/ROW is the model for Europe and the rest of the world
Safety
General
The modem is designed for and intended to be used in fixed and mobile applications. “Fixed” means
that the device is physically secured at one location and is not able to be easily moved to another
location. “Mobile” means that the device is designed to be used in places other than fixed locations.
RF Safety
Due to the possibility of radio frequency (RF) interference, it is important that you follow any special
regulations regarding the use of radio equipment. Follow the safety advice given below.
Caution: Maintain a separation distance of at least 20 cm (8 inches) between the transmitter’s
antenna and the body of the user or nearby persons. The modem is not designed for or
intended to be used in portable applications within 20 cm of the user’s body.
Check your local standards regarding safe distances, etc.
●Operating your device close to other electronic equipment may cause interference if the equipment
is inadequately protected. Observe any warning signs and manufacturers’ recommendations.
●Different industries and businesses restrict the use of cellular devices. Respect restrictions on the
use of radio equipment in fuel depots, chemical plants, or where blasting operations are in process.
Follow restrictions for any environment where you operate the device.
●Do not place the antenna outdoors.
●Switch OFF your wireless device when in an aircraft. Using portable electronic devices in an aircraft
may endanger aircraft operation, disrupt the cellular network, and is illegal. Failing to observe this
restriction may lead to suspension or denial of cellular services to the offender, legal action, or both.
●Switch OFF your wireless device when around gasoline or diesel-fuel pumps and before filling your
vehicle with fuel.
●Switch OFF your wireless device in hospitals and any other place where medical equipment may be
in use.

Chapter 1 –Product Description and Specifications
6 Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide
Sécurité RF
En raison de la possibilité d'interférences de radiofréquence (RF), il est important que vous suiviez une
quelconque réglementation concernant l'utilisation du matériel radio. Suivez les conseils de sécurité ci-
dessous.
ATTENTION: Maintenir une distance d'au moins 20 cm (8 po) entre l'antenne du récepteur et le corps
de l'utilisateur ou à proximité de personnes. Le modem n'est pas conçu pour, ou destinés
à être utilisés dans les applications portables, moins de 20 cm du corps de l'utilisateur.
Vérifiez vos normes locales touchant les distances de sécurité, etc..
●Fonctionnement de votre appareil à proximité d'autres appareils électroniques peuvent causer des
interférences si l'équipement est insuffisamment protégé. Respectez les panneaux d'avertissement
et les recommandations du fabricant.
●Différentes industries et les entreprises limitent l'utilisation des appareils cellulaires. Respectez les
règlements sur l'utilisation des équipements radio dans les dépôts de carburant, les usines
chimiques, ou lorsque des opérations de dynamitage sont en cours. Suivez restrictions pour
n'importe quel environnement où vous utilisez l'appareil.
●Ne pas placer l'antenne à l'extérieur.
●Éteignez votre appareil sans fil dans un avion. Utilisant des dispositifs électroniques portables dans
un avion peut mettre en danger le fonctionnement de l'avion, peut perturber le réseau cellulaire, et
est illégal. Le non-respect de cette restriction peut entraîner la suspension ou le refus des services
cellulaires au contrevenant, une action en justice, ou les deux.
●Éteignez votre appareil sans fil lorsque autour de l'essence ou pompes diesel-carburant et avant de
remplir votre véhicule avec du carburant.
●Éteignez votre appareil sans fil dans les hôpitaux et tout autre endroit où l'équipement médical peut
être utilisé.
Vehicle Safety
●Do not use your MultiModem while driving.
●Respect national regulations on the use of cellular telephones in vehicles. Road safety always comes
first.
●If incorrectly installed in a vehicle, the operation of wireless MultiModem telephone could interfere
with the correct functioning of vehicle electronics. To avoid such problems, be sure that qualified
personnel have performed the installation. Verification of the protection of vehicle electronics
should be part of the installation.
●The use of an alert device to operate a vehicle’s lights or horn on public roads is not permitted.
Maintaining Your Modem
●In the unlikely event of a fault in the Wireless MultiModem, contact Multi-Tech Technical Support.
●When maintaining your device:
Do not attempt to disassemble the device. There are no user serviceable parts inside.
Do not expose your device to any extreme environment where the temperature or humidity is
high.
Do not expose the device to water, rain, or spilled beverages. It is not waterproof.
Do not place the device alongside computer discs, credit or travel cards, or other magnetic
media. The information contained on discs or cards may be affected by the device.
Using accessories, such as antennas, that Multi-Tech has not authorized or that are not
compliant with Multi-Tech's accessory specifications may invalidate the warranty.
●If the device is not working properly, contact Multi-Tech Technical Support.

Chapter 1 –Product Description and Specifications
Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide 7
User Responsibility
Respect all local regulations for operating your wireless device. Use the security features to block
unauthorized use and theft.
Package Contents
Unbundled Package
Modem with No Accessories
Bundled Package
Modem with Accessories
1 modem
1 mounting bracket
1 fused DC power cable
1 Quick Start Guide
Note: You must supply bracket screws
and an antenna.
1 modem
1 mounting bracket
1 antenna
1 serial cable
1 DC power supply/cable (varies)
4 rubber feet
1 Quick Start Guide
Note: You must supply bracket screws.
Note: Your wireless provider supplies the SIM card.
General Specifications
Power Requirements
5 V to 32VDC; 400mA Average @5V, 1A Peak @ 5V
Mechanical Dimensions & Weight
4.3" L x 2.4" W x 0.94" H; 4.2 oz.
(11 cm x 6.1 cm x 2.4 cm; 119 g)
Connectors & Fasteners
Antenna Connection type: SMA jack
Serial Connector: DE15
Pins: RS232 link, audio link, BOOT, RESET
Power Connector: 2.5mm miniature power jack
SIM receptacle: standard 3V
Operating Temperatures
-30° to +70°C
Storage Temperatures
-40° to +85°C
Humidity
Relative humidity 20% to 90% noncondensing
Certifications
CE Mark, R&TTE
EMC: FCC Part 2, 15, 22, 24, EN 55022 & EN 55024
Safety: cUL, UL 60950, EN 60950
Network: PTCRB
Functions –GSM/GPRS Modes
Mode
Description
Standard
Quad Band 850/900/1800/1900 MHz
Interface
Serial interface RS-232. V.24/V.28 Autobauding function.
SMS
Mobile Originated (MO) and Mobile Terminated (MT) SMS Mode Text & PDU point to point.
Cell broadcast in accordance with GSM 07.05.
Data
Data circuit asynchronous, transparent, non-transparent up to 14,400 bits
GPRS
Class 10. Coding schemes: CS1 to CS4.

Chapter 1 –Product Description and Specifications
8 Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide
Electrical Specifications
Switching on/off
The device is permanently powered (when connected to the power
supply).
Voltage Range
Voltage range : 5 to 32V DC
GND : 0V
Over voltage and under voltage
Correct operation of the wireless MultiModem in communication mode is
not guaranteed if input voltage falls below 5V.
Input/output electrical characteristics for external connections
Parameters
GSM/GPRS 850/900
GSM/GPRS 1800/1900
Unit
Typ.
Typ.
Input Supply Voltage
5
13.2
32
5
13.2
32
V
Input peak supply current in comm. mode at Pmax
1
.4
.2
1
.4
.2
A
Input average supply current in comm. mode at Pmax
360
150
75
300
125
70
mA
Input average supply current in idle mode
30
10
10
30
10
10
mA
RF Specifications
GSM 850
EGSM 900
GSM 1800
GSM 1900
Frequency RX
869 to 894 MHz
925 to 960 MHz
1805 to 1800 MHz
1930 to 1990 MHz
Frequency TX
824 to 849 MHz
880 to 915 MHz
1710 to 1785 MHz
1850 to 1910 MHz
RF Power Stand
2W at 12.5% duty
cycle
2W at 12.5% duty
cycle
1W at 12.5% duty
cycle
1W at 12.5% duty
cycle

Chapter 1 –Product Description and Specifications
Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide 9
Antenna Specifications
GSM/EGSM Antenna Requirements/Specifications
Frequency Range:
824 –960 MHz / 1710 –1990 MHz
Impedance:
50 Ohms
VSWR:
<2.0:1
Typical Radiated Gain:
3 dBi on azimuth plane
Radiation:
Omni
Polarization:
Vertical
Wave:
Half Wave Dipole
Antennas Available from Multi-Tech Systems, Inc.
Description
Part Number
Hinged Right Angle 900/1800 MHz Cellular Modem
Antenna
ANF1-1HRA
Hinged Right Angle 800/1900 MHz Cellular Modem
Antenna
ANF21HRA
Hinged Right Angle 850/900/1800/1900 MHz Cellular
Modem Antenna
ANQB-1HRA
PTCRB Requirements Note
There cannot be any alteration to the authorized antenna system. The antenna system must be the
same type with similar in-band and out-of-band radiation patterns and maintain the same specifications.
FCC Requirements Note
The antenna gain, including cable loss, must not exceed 3.0 dBi at 1900 MHz / 1.6 dBi at 850 MHz for
mobile operating configurations and 7.0 dBi at 1900 MHz / 2.3 dBi at 850 MHz for fixed mounted
operations, as defined in 2.1091 and 1.1307 of the rules for satisfying RF exposure compliance.

Chapter 1 –Product Description and Specifications
10 Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide
Interfaces
LEDs
TD
Transmit Data. Lit when modem is transmitting data.
RD
Receive Data. Lit when modem is receiving data.
CD
Carrier Detect. Lit when data connection has been established.
LS
Line Status.
Continuous “on” state indicates that the wireless modem is not registered on the network.
Flashing state indicates registration on network.
Off state. Modem is off (not ready) or in download mode.
TR
Terminal Ready. Commonly called “Data Terminal Ready.” This is a readiness signal from the
PC.
PWR
Power. Indicates presence of DC power when lit.
RS232 15-Pin Connector Pinout
10 11
6
15
15
PIN
EIA
CCIT
Designation
RS-232
1
DCD
109
Data Carrier Direct
6
RX
104
Receive Data (out)
2
TX
103
Transmit Data
8
DTR
108.2
Data Terminal Ready
9
GND
Signal Ground
7
DSR
107
Data Set Ready
12
RTS
105
Request to Send
11
CTS
106
Clear to Send
13
RI
125
Ring Indicator
Audio
4
MICROPHONE (+)
5
MICROPHONE (-)
10
SPEAKER (+)
15
SPEAKER (-)
Boot
3
BOOT
For factory use only.
Reset
14
RESET
To reset, connect to GND momentarily
(typical: 2mSec). Open for normal operation.
AT Command Information
AT commands for the GPRS wireless modem are published in a separate reference guide. You can find
this guide on the Multi-Tech website.
IP commands for GPRS modems are also published in a separate reference guide. This guide is also
included on the Multi-Tech website.

Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide 11
Chapter 2 –Activation and Installation
Activating Your Wireless Account
Some Multi-Tech cellular modems have been pre-configured to operate on a specific cellular network, such as
Sprint and Verizon Wireless.
However, before you can begin to use the modem, you must set up a cellular data account with your cellular
network provider. Refer to Multi-Tech’s Cellular Activation website http://www.multitech.com/activation.go for
information on activating your cellular modem.
Phone Numbers for the Wireless Modem
Every wireless modem will have its own unique phone number. The phone number may simply be given to you
by your wireless service provider or it may be on the SIM card or both. Wireless provider implementations may
vary.
Inserting the SIM Card into the Holder
The wireless MultiModem requires the power supply connection to begin operation. It also requires a SIM card
(Subscriber Identity Module) to operate on a GSM network.
To install the modem:
1. Using your fingernail or a small wedging tool (e.g., a small screwdriver), pry off the SIM cover.
2. Insert the SIM card into the holder.
3. Verify that the SIM card fits into the holder properly and then replace the cover.

Chapter 2 –Activation and Installation
12 Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide
Connecting the Antenna, Serial Cable, and Power
1. Connect a suitable antenna to the SMA connector (see antenna specifications on page 9).
2. Connect both sides of the serial and control cable (15-pin Sub D connector on the modem side).
3. Plug the power supply cable into the modem.
Connecting Two-Piece Transformer Power Supply (International)
1. Connect the AC cord receptacle into the transformer block.
2. Connect the AC cord plug into the mains power outlet.
Connecting One-Piece Transformer Power Supply (North America)
1. Connect between the MultiModem power receptacle and the mains power outlet.
Connecting Optional Direct DC Power
1. Connect the fused DC power cable into the DC power connector on the modem.
2. Attach the two wires at the other end of the fused cable to a DC fuse/terminal block on a vehicle in which
you are mounting the MultiModem.
3. Connect red wire to the "+" (positive) and black wire to the "–" (negative). Be sure the GND connection is
correct.
Note: Over-voltage protection is provided on the device. For more thorough protection, you may want to add
additional filtering to the DC input.
Note: For automotive application: according to the type of application, you can use permanent “+” or key-
switched “+”. Connect the power supply to its source (for example, in a mobile situation, to the
vehicle’s DC fuse/terminal block).

Chapter 2 –Activation and Installation
Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide 13
Optional –Attaching the Modem to a Flat Surface
To mount the Wireless MultiModem:
1. Obtain mounting screws (two are needed) that are appropriate for the surface on which you will mount the
modem. For example, you might use two 6-32 self-tapping screws 5/8” in length to mount the modem in a
truck cab, on the wall behind the passenger’s seat.
2. Typically you mount the unit against a flat surface where you can drill holes. Separate the mounting holes by
125mm or 4 -15/16 inches, center-to-center.
3. Drill the mounting holes at the desired mounting location.
4. Slide the mounting bridles into the corresponding slots on the backside of the modem chassis.
5. Attach the modem with two screws to the mounting surface at the desired location on the equipment.
Installing the Modem Driver
Before you Begin
●If you are operating the modem on a PC that runs a Windows operating system, download the MultiModem
driver from the Multi-Tech website.
Note: If you are running Linux, you don’t need a driver for serial modems.
●Make sure your PC’s operating system is compatible with the wireless modem. The modem is compatible
with Windows Vista, XP, 2003, 2000, and Linux.
●Ensure you have the required equipment handy:
●One MTCBA-G modem
●A RS-232 cable to connect the modem to the
Note: These instructions are a basic guide to help you install the Multi-Tech Wireless modem driver. You may
see differences in your setup based upon your version of Windows and your Windows settings.
Installing the MultiModem Driver on a PC Running Windows Vista/XP/2003
These installation steps assume your PC is running a Windows Vista, Windows XP or Windows 2003 operating
system.
To install the driver on your PC:
1. From the Start menu, select Control Panel.
2. In the Control Panel window, double-click Phone and Modem Options.

Chapter 2 –Activation and Installation
14 Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide
3. In the Phone and Modem Options window, click the Modems tab.
4. To add a new modem, click Add.
The Add New Hardware wizard window opens, and steps you through the installation.
5. On the Install New Modem panel, click Don’t detect my modem, I will select it from a list.
6. Click Next. Another installation wizard panel appears.

Chapter 2 –Activation and Installation
Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide 15
7. To browse for the driver file on your PC, click Have Disk. Click Next.
8. In the next panel, click Browse.
9. Browse to the location where you placed the driver that you downloaded from the Multi-Tech website.
10. Select the driver for your modem and click Next.
11. The next installation wizard panel asks you to select the com port to which the MultiModem is connected.
●If you know which port your modem is on, click that port
●If you don’t know the port, select COM1 (most common).

Chapter 2 –Activation and Installation
16 Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide
12. Click Next.
13. To finish the install, click Finish.
You have successfully installed the MultiModem driver.
Verifying That Your Modem Has Been Installed Successfully
1. After installing the Multi-Tech modem driver, you return to the Phone and Modems Options window.
2. Make sure that the modem is listed in the Modem column. Also ensure that the correct COM port is listed in
the Attached To column.
3. Highlight the modem. Click Properties.
4. A Properties window opens. Select the Diagnostics tab.
5. Click Query Modem. Windows queries the Multi-Tech modem.
6. To make sure that the modem is correctly being queried, check the modem’s LED lights.
●The TR light should be on.
●The TD and RD lights should flicker.
7. If the query works, the second box shows the columns Command and Response.
The modem is properly installed and ready for use.
8. To close the modem Properties window, click OK.
9. To close the Phone and Modem Options window, click OK.

17 Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide
Chapter 3 –Using Your Wireless Modem
This chapter describes how to use your wireless modem. It describes how to check your modem’s signal
strength and how to ensure your modem is registered on a network.
Obtaining a Phone Number for the Wireless Modem
Every wireless modem has a unique phone number. The phone number may simply be given to you by
your wireless service provider or it may be on the SIM card or both. Wireless provider implementations
may vary.
Checking Signal Strength and Network Registration
This section describes commands that you can use to check signal strength and roaming status.
Before You Begin
Ensure you have access to a terminal application such as HyperTerminal
To verify signal strength and roaming status, you must use a terminal application such as
HyperTerminal. To open this program in Windows XP or Windows 2003, go to Start > All Programs >
Accessories > Communications > HyperTerminal.
Other Windows operating systems have similar paths to HyperTerminal. If you cannot find the
HyperTerminal application, check system’s online help file for further information.
Downloading the AT reference guide from the Multi-Tech website
You can use AT commands to operate, configure, and query your modem. You can use the Multi-Tech
website to download a reference guide that describes the GPRS commands.
Verifying Signal Strength
1. Using HyperTerminal, type AT+CSQ.
2. The modem responds with the received signal strength (rssi).
RSSI ranges from 0 to 31.
Signal Strength Verification –RSSI
21 –31
Exceptional
11 - 20
Average
0 - 10
Weak or Insufficient
99
No signal
3. The modem responds with the received signal strength (rssi) and the channel bit error rate (ber).
BER ranges from 0 to 7. Seven is the highest error rate.

Chapter 3 –Using Your Wireless Modem
18 Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide
Checking Network Registration and Roaming Status
To verify that the wireless MultiModem has been registered on the wireless network:
1. Using HyperTerminal, type AT+CREG?
The modem responds in one of the following ways:
Network Registration Verification
Value
Network Registration Status
0,0
The modem is not registered on any network
0,1
The modem is registered on the home network
0,5
The modem is registered on a network and it is roaming
Note: If the modem indicates that it is not registered, verify the signal strength to determine if the
problem is the strength of the received signal.
Checking the Modem’s Identity
Use the ATI command to check the modem’s identity.
1. To display manufacturing data, type ATI0
Note: This command uses the capital letter I after AT.The command ends in a zero.
Manufacturing data displays, for example, Wavecom Modem Multiband G850 1900
2. To display the software version, type ATI3
The software version displays, for example, 651_09gg...
3. To display modem data features, type ATI6
Modem data features appear, such as data rates, data modes, fax classes.
Establishing a Voice Call
1. Enter PIN code, if one is required by your wireless provider.
a. Type AT+CPIN=1234
b. Responses include:
OK (PIN Code accepted)
+CME ERROR : 16 (Incorrect PIN Code)
+CME ERROR : 3 (PIN already entered [with +CMEE : 1 mode])
2. To initiate a voice call:
a. Type ATD1234;
Note: Don’t forget the semicolon “;” at the end, which indicates voice calls.
b. Responses include:
OK (Communication established)
CME ERROR : 11 (PIN Code not entered [with +CMEE : 1 mode])
CME ERROR : 3 (Operation not allowed)

Chapter 3 –Using Your Wireless Modem
Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide 19
3. To initiate an emergency call:
a. Type ATD112; (Note: Don’t forget the semicolon “;” at the end, which indicates voice calls)
b. Responses include:
OK
4. To hang up:
a. Type ATH
b. Responses include:
OK
Establishing a Circuit-Switched Data (CSD) Connection
A Circuit-Switched Data Connection makes the wireless modem work similar to a regular analog
modem. You must have CSD service in order to make a CSD call.
Note: Your wireless service provider charges airtime usage for these connections.
Establishing a Connection
1. Use HyperTerminal or a terminal application, type the following command:
ATD<phone number>
Notes:
●The phone number you are calling is entered between the displayed brackets. Do not type
additional brackets. For example, type only ATD 8585551212. 8285551212 is typed between the
brackets.
●This command tells the modem to inform the wireless network that you are initiating a CSD
modem call. If you are dialing to another modem, the remote modem should answer and a
connection between the two modems will be established. If you include a semi-colon (;) at the
end of the dialing string, the modem will instead initiate a Voice call to the phone number
dialed.
Disconnecting
1. To disconnect, type: +++
2. Wait about two seconds to see an OK response.
3. Then type: ATH
Note: +++ is the escape sequence and ATH is the Hang-up command.
Answering a Circuit-Switched Data (CSD) Connection
A Circuit-Switched Data Connection makes the wireless modem work similar to a regular analog
modem. You must have CSD service in order to answer a CSD call.
There are three phone numbers for GSM: the voice number, the data number, and the fax number. All
are provided by the carrier.
To answer a call:
1. To establish a connection, call into the modem by dialing the data number provided by your carrier.
2. To answer a call, when you see the RING responses on the terminal screen, enter ATA <cr>.
3. To set auto-answer, enter ATS0=x

Chapter 3 –Using Your Wireless Modem
20 Multi-Tech Systems, Inc. MultiModem GPRS Wireless Modem User Guide
This sets the modem to auto-answer. The call will be answered after the number of rings entered. x
stand for the number rings.
4. Call the number provided to you by the carrier.
To disconnect:
1. Type: +++
2. Wait about one second to see an OK response.
3. Type ATH
Using Short Message Services (SMS)
Sending a Short Message to a Specified Number
1. Type AT+CMGS="8585551212" <press Enter>
2. Then type your message: Please call me soon. <press ctrl Z>
3. The modem may respond with +CMGS:<mr> OK
Writing a Message to Memory
You can store a message to send it at a later date.
1. Type AT+CMGW="8585551212" <press Enter>
2. Type the message. <press ctrl Z>
3. The modem may respond with +CMGW: 4 OK (The message is stored in the index as message 4.)
Sending a Message from Storage
1. Type AT+CMSS=x,"8585551212" <press Enter>
2. The modem may respond with +CMSS: 1 OK (The transmission is successful. One SMS message is
sent.)
Note: The xrepresents an index location.
Viewing a List of Stored Messages
1. Type AT+CMGL=x <press Enter>
2. For x, substitute one of the following:
"REC UNREAD" Shows received unread messages.
"REC READ" Shows received read messages.
"STO UNSENT" Shows stored unsent messages.
"STO SENT" Shows stored sent messages.
"ALL" Shows messages.
3. The modem will respond AT+CMGL: 1,"REC UNREAD","8585551212",1...
4. The modem will continue until all UNREAD messages, numbers, and index number are listed.
Reading a Stored Message
1. Type AT+CMGR=x<press Enter>
2. The modem may respond with +CMGR: "REC READ", "8585551212", ......
Note: The xrepresents an index location.
Deleting a Stored Message
1. Type AT+CMGD=x,n <press Enter>
2. If you want to delete one message at a time, do not enter a value for n.