Chapter 3 - Using Your Wireless Modem; Phone Numbers For The Wireless Modem; Examples Of Useful At Commands; Hyperterminal - Multitech MultiModem iCell User Manual

Chapter 3 – Using Your Wireless Modem
Phone Numbers for the Wireless Modem
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Every wireless modem has a unique phone number.
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Your wireless service provider may give you the phone number. The number may be on the SIM card. Wireless
provider implementations may vary.
Examples of Useful AT Commands
HyperTerminal
To verify signal strength and roaming status, use a terminal application such as HyperTerminal. To open this program in
Windows Vista or XP, go to Start > All Programs > Accessories > Communications > HyperTerminal. Other Windows
operating systems have similar paths to HyperTerminal. If you cannot find HyperTerminal, use your system's online Help file.
AT Commands
You can use AT commands to operate, configure, and query your modem. AT commands for the MultiModem iCells are
published in separate Reference Guides. You can find these guides on the Multi‐Tech web site.
The following two commands let you query signal strength and roaming status.
Verifying Signal Strength
Using HyperTerminal, type AT+CSQ
1.
The modem responds with the received signal strength (rssi).
2.
The modem responds with the received signal strength (rssi) and the channel bit error rate (ber).
3.
RSSI ranges from 0 to 31.
AT+CSQ xx Values
0 ‐ 10
11 ‐ 20
21 – 31
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BER ranges from 0 to 7 (Seven is the highest error rate).
Checking Network Registration and Roaming Status
To verify that the MultiModem is registered on the wireless network:
Open HyperTerminal, and type AT+CREG? for most models.
1.
The modem responds to AT+CREG? 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
Multi‐Tech Systems, Inc. MultiModem iCell User Guide
Signal Strength Verification – RSSI
Signal Strength
Weak or Insufficient
Average
Exceptional
No signal
LED Bars
1 Bar LED is lit
1 Bar and 2 Bar LEDs are lit
1 Bar, 2 Bar, 3 Bar LEDs are lit
No light
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