How to send DTMF signal in Symbian S60

Question

I am new to Symbian development. I am developing a VOIP [SIP protocol] app for Nokia Symbian S60 3rd edition. I want to send DTMF signal through my app. But couldn't find any clue. So how can I send and catch DTMF signals in my app.

Thanks in advance.

Answer 1

in VoIP world you send SIP INFO messages with the DTMF data to the SIP server. For example to send the digit '1':

INFO sip:[email protected] SIP/2.0
Via: SIP/2.0/UDP alice.uk.example.com:5060
From: <sip:[email protected]>;tag=d3f423d
To: <sip:[email protected]>;tag=8942
Call-ID: 312352@myphone
CSeq: 5 INFO
Content-Type: application/dtmf-relay
Content-Length:    22

Signal=1
Duration=160

See also this link.

If you want "traditional" DTMF messages over the RTP, the best way is to have the DTMF signals recorded (1.wav, 2.wav, etc) and play them it back during the call.