User's Guide ______________________________________________________________________  
218 _________________________________________________________________ M211296EN-A 
Troubleshooting GSM/GPRS Modem 
Below are listed some useful tips on how to troubleshoot problems with 
GSM connection. 
1.  Use a cellular phone to verify that the signal strength in the site is 
sufficient or that the system SIM card has access to the network. 
2.  Open a command connection to the GSM modem by entering the 
following commands to AWS Client terminal window in QML 
logger command mode: 
 open MOD1_1 
ATE 
3.  To test the GSM modems with the AT commands, refer to Table 59 
below.  
Table 59  Test Commands for GSM/GPRS Modems  
Parameter Command Value 
Network registration  AT+CREG?  Registration status: <n>, <stat>,
where <stat> 
0 = Not registered 
1 = Registered to home network
2 = Searching 
3 = Registration denied 
5 = Registered, roaming 
AT+COPS?  Returns the used operator Available operator 
AT+COPS=?  Queries all available operators, 
can be used to refresh the 
connection 
Operator selection  AT+COPS=0/1 0 = Automatic 
1 = Manual 
Signal quality  AT+CSQ  Receive level 
31 = Best 
0 = Worst 
99 = Not known 
Under normal conditions, value 
should be 10 or above.