Garbled voice quality

Hello all,

We are currently running Asterisk v1.4.21.2 on a Linux box. Occasionally, when talking with people outside the network, the incoming voice quality degrades considerably.

The only way to describe it is to say the person on the other end sounds like a Cylon from the old Battlestar Galactica television show. The person on the other end of the line is not aware of any problem. The sound quality is perfectly fine for them.

We’ve discovered that we can “fix” the problem by placing the call on hold and then immediately taking it off hold.

I also found that I could reproduce the problem by dialing an AT&T phone number and proceeding through the menu tree until a certain point, at which time the sound quality goes south.

Any ideas on what this might be?


generally garbled audio is the result of latency and/or dropped RTP packets. It sounds like your upload is working OK, but your download is struggling a bit.

Does your network gear support QoS?

I am having the same issue. An we are running QoS and network traffic seems to be low.


You need to test the link quality, also you may well find that the ISPs backbone is just swamped with traffic. DOnt forget, Most of the world is on Holiday today so browsing traffic will be different to usual.


We have PRI lines coming in from the phone company. So no internet involved in our case. It is only hear on our end. Everything sounds fine to remote caller.

Hello, it is timing source problem. If you have any card able to provide timing use it.

robert, did you ever find the problem?