I have a Huawei USB stick (E3372h-320) running under Linux. I configured usb_modeswitch so it's switched into the modem mode (or "stick mode") rather than the "hilink" mode.
I correctly get three /dev/ttyUSB* devices, and I'm playing around with AT commands.
The modem correctly registers in the network, AT+COPS? shows it's registered. I am definitely able to send and receive SMS messages without problems (using the AT+CMGF=1 + AT+CMGS=<number> commands. AT+CSQ gives good signal strength.
The SIM card works perfectly in a mobile phone.
So far so good. However, now I'm trying to get the modem to dial some number, and that's where things are not working.
Any syntax for the ATD<number> command I tried (with/without quotes around the number, with/without semicolon at the end, with/without country code, with T, with P) resulted in an immediate NO CARRIER response from the modem.
Now I could certainly be missing something, but the main thing I'd like to understand now is: Is ATD supposed to be working in my scenario? Does it depend on the modem? On the operator? On the SIM? On something else? How do I check? Of course if it cannot work or is not supposed to be working, it's pointless for me to waste more time trying.
