Weird Echo() issue

Hello community !

I have a pri/sip gateway audiocode mediant 1000 (4 E1) connected to an asterisk 13.3.2.

When I loopback 2 E1 together, route a call from asterisk to the audiocode, through the loopback, back to the audiocode, then to the asterisk and finally to the echo application, everything works fine.

When I connect the E1 to a EuroISDN E1 from an operator, and place an incoming through the audiocode, then asterisk and an extension, audio is clear, two ways, no problem.

However… if I route the same call to the same echo application as before, echo is garbled - ie what is said on the pstn phone is echoed back by asterisk garbled. But the weird comes here… if I record with MixMonitor, audio is clear, both ways !!! and the played-back message just before the echo() is also fine.
Codecs are G711a in all cases, and nothing is changed apart from the E1 not being in loopback.

I can not understand why the echo function is not working in this last config !

Any ideas ?


That implies there is excessive jitter. The phone cannot cope with the jitter in real time, but the MixMonitor recording can cope with it as it is not being played back in real time.

Thanks - I’ll look at this - but everything is on the same lan, not loaded