[Asterisk-Users] A-B ok; B-C ok; A-C Crap

[George Pajari]

Here's a puzzlers for you expert Asteriskians:

Person A in Australia with Xten-Lite connects to:
Person B on an Asterisk server in Vancouver, Canada (B is on analog phone to
FXS port)
quality is fine.

Person B on an Asterisk server in Vancouver IAX trunks to
our Vancouver PSTN gateway (running Asterisk and connected to a PRI) and
calls (placing a local landline call) to
Person C on a regular PSTN phone line
quality is fine.

Person A links to B, trunks to C, connects to local Vancouver number.
quality in both directions is crappy -- choppy to the point of
unintelligible.

So each leg tested separately works fine. The two put together do not.

Where should we look? What parts of which configurations do you need to see
to diagnose the problem?

Thanks for any and all suggestions.

g.