We use VS-GW1202 with VS-GWM420G modules.
The task is to receive a call from GSM-module and send some DTMF-signals towards A-side.
So far we didn't find any solution except playing prerecorded audio-files with needed tones, but in this case quality of audio is very poor because of transcoding.
Is there any way to make a module snd DTMF-signal using signalling channel on air intreface according to GSM-standarts?
