Is it possible to read signal quality from GSM/CDMA modems while connected?

Question

I know I can communicate with GSM/CDMA modems using AT commands. However, as far as I know this doesn't work when connected - is there a way to read status information (signal strength, GSM/HSDPA mode etc) while connected?

I am not sure if modemmanager will produce the information, I tried it with Nokia phone and it didn't - however I would like it mostly for the Qualcomm chipset modems (Huawei), does anyone have any experience reading realtime signal information from these modems?

Answer 1

As far as I am aware you can use AT+CSQ command to receiving the signal quality. This is independent of whether the modem is connected to an operator or not. My experiences have been with Wavecom, Siemens, and Sierra Wireless modems.

Request:

AT+CSQ=?

Response:

+CSQ: <rssi>,<ber>

Where <rssi> is received signal strength indication and <ber> is the bit error rate.

There is also the possibility of getting regular unsolicited updates but this is normally modem/manufacturer specific. For example Wavecom modems use AT+CCED, Siemens use AT^SMOND.