asterisk users - Jun 2005 - Garbled speech - strange problem.

I have two Asterisk boxes connected via IAX2 trunking so that calls made on
ServerA to extensions on ServerB connect over a Cable TV connection. As we
are close, the latency is only 16ms and this has worked very well for weeks
to connect these offices together.

Suddenly all of the calls from ServerA have garbled text, sounding like the
users are underwater. They hear perfect sound from ServerB users. Nothing
has changed that I know of. There is plenty of bandwidth, no packet loss,
and the calls use the ulaw codec. Extention to extension on ServerA are
fine.

Calls made from ServerB to another trunked PBX work beautifully, but these
go over a different internet connection.

I am pulling my hair out to find a solution.

Chris Mason