Getting GPRS signal strength

Hello everybody,

I am currently using the AT+CSQ command in order to get the GPRS signal strength once the connection is stablished by sending the scape secuence and then entering in command mode to get the signal value. I sometimes get the expected value but I very frequently get 99,99, what means “not known or not detectable”.

Any idea on how to solve this issue?

Thanks in advance,

Best regards