Archived from groups: alt.cellular.gsm (More info?)
I am trying to use my M1203b fastrack modem for voice calls. I have read the documentation including the AT commands required for voice comm (VGT, VGR etc.) but no success. I think it is a hardware problem :-) in particular a problem with the way I'm connecting the modem to a speaker.
The modem has a serial connection and a telephone cable attached to it. The cable terminates in a RJ11 connector. I tried to:
a)Plug it into a landline telephone. After I accepted the connection "ATA", I couldn't hear anything coming through the phone handset
b)Plug it into a "Telephone Recording Adapter". This adapter takes in a RJ11 plug and sends the signal to a speaker (which can be used for recording). (There's another cable, but not relevant to this discussion). Again I made a call, but there was no output from the speakers.
I guess I'm doing something wrong here. Can anyone see what the problem could be?
Actually yes, you can use commercially available '3G' modems to do this, regardless of what previous answers claim. It is true that you can't use any 3G modem, most does not support this (although this is due to drivers often. Many of the 3G chips that are used supports this..)
Here is one USB 3G modem that supports this for example: Huawei K3520. Here is a blog post describing who to enable this on many Huawei modems.
Most branded modems from operators (at least i Europe) are just rebranded Huawei modems, so if you already have a modem you might be able to hack it to support voice calling.