[Asterisk-Users] Problems with a combination of AVM B1 and HFC-S on Kernel 2.6.x

[Uwe Betz]

Hello List!

Several users of a german VoIP-Forum experience the following similar 
problems when using CAPI with an active ISDN-Card AVM B1 PCI connected 
to the PSTN and a HFC-S in NT-Mode used as an "internal" S0-Bus to 
connect ISDN-Phones.

The problem is, that when making a phone call from an ISDN-Phone 
connected to the HFC-S-Card that is meant to be routed to the PSTN 
through the AVM B1, the voice quality is very bad. It sounds as if 
someone has a really bad, bad cold.

What makes us wander is, that if a call is made from a SIP-client 
through the AVM B1 to the PSTN, everything ist fine. Calls between 
SIP-clients and ISDN-Phhones connected to the HFC-CArd are also ok.

In addition one user found that if one monitors/records a phonecall made 
from an ISDN-Phone to the PSTN through the AVM B1, the recorded sound is 
also fine, only the "live" sound is that bad and we have no more ideas 
what to try to figure out where the problem is.

What we heard, but we still have to verify this is, that on a Linx with 
Kernel 2.4 everything seems to work. But this is still unverified. The 
Kernel is 2.6.8 in my case the actual updated Kernel of a SuSE 9.2 
Distribution.

We were also testing different Motherboards and made sure that there are 
no IRQ-Conflicts between HFC and AVM card, etc. The Test-Systems had no 
load and are running smoothly.

Any ideas?

Thanks,

Jui