[Asterisk-Users] Sound quality poor everywhichway

[Rob Scott]

I am hoping someone is going to bite on the sound quality issue.

I have Asterisk connected via a Conceptronics HFC-S card to an Elmeg
ICT880 PBX internal extension line. Running Asterisk 1.0.3 and latest
Bristuff.
I have firefly and Xlite clients running on Windows XP.

Calls between Xlites through Asterisk seem to be fine.
Calls from anything to ISDN is terrible whatever settings I change.
Calls on VoiP for example to the 411 service on FWD through my Asterisk
box are not as good as using the same service by phone, not by a long
way. There is distortion and also a kind of harmonic tone in the
background when the person is talking on the other end (i.e. it sound
like someone is playing a low toned kazoo in time to the person
talking).

Everything is going ulaw.
It is on a quiet network.

The Desktop is an IBM ThinkCenter with built in audio - 2.66 GHz P4.

Anyone got any ideas?
I am pulling my hair out here trying to get this working.