mobile DTMF timing

mad mad at
Thu Jan 26 18:02:01 UTC 2012

Hi list, hi Jolly,

I just tested the DTMF support on a real network and discovered that the timeout of 70ms for receiving the Start DTMF ACK is too short. The consequences are many repeated Start DTMF messages, never received ACKs and no tone is played. 
Using a timer value of 170ms in mnccms.c:759 fixes this for that network.
Unfortunately I didn't found - or overlooked - a mandatory timeout value for Ta in TS 23.014 which the MSC has to meet. 
Is that undefined in the standard and where came the 70ms from?


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