Chapter 3 – Using Your Wireless Modem
Multi-Tech Systems, Inc. MultiModem EDGE USB Wireless Modem User Guide 21
Chapter 3 – Using Your Wireless Modem

Phone Number for the Wireless Modem

• Every wireless modem will have its own unique phone number.
• The wireless modem’s phone number may simply be told to the subscriber by the service provider or
be on the SIM or both. Wireless provider implementations may vary.

Examples of Useful AT Commands

A Note About HyperTerminal
In order to verify signal strength and roaming status, you must use a terminal application such as HyperTerminal. To
open this program in Windows XP, go to Start > All Programs > Accessories > Communications >
HyperTerminal. Other Windows operating systems have similar paths to HyperTerminal. See your system’s online
Help if you cannot find it.
A Note About AT Commands
AT commands can be used to operate, configure, and query your modem. A reference guide to the EDGE commands
is included on the MultiModem CD and on the Multi-Tech Web site.
The following two commands let you query signal strength and roaming status.

Verify Signal Strength

Using HyperTerminal, type AT+CSQ
The modem responds with the received signal strength (rssi) and the channel bit error rate (ber).
RSSI ranges from 0 to 31.
Signal Strength – RSSI
10 - 31 Sufficient
0 - 9 Weak or Insufficient
99 Insufficient
BER ranges from 0 to 7 (Seven is the highest error rate).

Checking Network Registration and Roaming Status

Using HyperTerminal, type AT+CREG?
The modem will respond in one of the following ways:
+CREG: 0,0 (this tells you that the modem is not registered on any network)
+CREG: 0,1 (this tells you that the modem is registered on the home network)
+CREG: 0,5 (this tells you the modem is registered on a network but it is roaming)
Note: If the modem is showing not registered, perform the procedure for verifying signal strength to determine
the strength of the received signal.

Checking the Modem’s Identity

Use the ATI command (Note: This command is illustrated using the capital letter i after AT)
• Type ATI
Product information displays. For example, Siemens MC75 Revision xx.yy (xx.yy is the software version)