static, choppy on call pilot when connecting via sip

[1998xj8]

cs1000 rev 6 connected to cs1000m rev 6 via sip..
the calls to voicemailseem choppy and low volume although direct calls to sets are ok... we use g711 20ms BQ but still have clarity problems just with one remote site.. is there best practice on vad..echo..or any setting where you can smooth out a choppy voice mail network connection. the network has QOS and no problem found

 

[janaya]

same problem here, but we send the call to a converged desktop user and the pipe over to the MCS5100 is SIP, and in another country, on the other side of the world.

But the same static, garbled sometimes no speech path when calls are routed to vmail.