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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.
