Specifications

Chapter 2 – Getting Started
23 MultiModem® iSMS Administrator’s Guide
Signal Strength
Signal Strength Command
To View Strength
For the SF 400/800 models without signal LEDs, signal strength can be determined by using the following AT command:
AT+CSQ. This command is the default setting on the Network Setup > Cellular Modem window. This works for the SF 100
as well.
AT Command Response Example
+CSQ: xx (For xx, see the values chart below)
Signal Strength Reference Table
The following table lists the meaning of the xx values in the signal strength response and explains how they correspond to
the number of LEDs lit for signal strength.
AT+CSQ Values Signal Strength SF 100 Signal LED Bars
0 to 6 Very weak signal No LEDs lit
7 to 14 Weak signal 1 Bar LED is lit
15 to 23 Stronger signal 1 Bar and 2 Bar LEDs are lit
24 to 31 Strongest signal 1 Bar, 2 Bar, 3 Bar LEDs are lit
99 Signal not detectable No LEDs lit
SF 100 Signal Strength LEDs
Using AT Commands to Check Network Registration and Roaming Status
Use this command to verify that the cellular modem has been registered on a wireless network.
1. In the command window, type AT+CREG?
2. The modem responds in one of the following ways:
Network Registration Verification
Value Network Registration Status
+CREG: 0,0 The modem is not registered on any network
+CREG: 0,1 The modem is registered on the home network
+CREG: 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.