IAX Trunk - Slow/Choppy/Robotic Voice


I have been investigating an issue with our Asterisk-to-Asterisk setup using IAX to solve the sound quality. The scenario can be shown as follows:

Cisco AS5350 -> Asterisk1 (us) - Asterisk2 (customer) - End-User.

The problem is that everytime there is an incoming call from the PSTN (AS5350), it is forwarded accordingly to the End-User but the voice is choppy/robotic/slow ( I hope you know what I mean). I have been playing around with many settings including disabling VAD in the Cisco, specifically set Asterisk to use internal timer (settings in the sip.conf). None of these works.

I’m having a similar issue. Did you ever resolve this?

Was there a resolution this issue? I’m experiencing the same issue.