[Asterisk-Users] No voice for SIP to ISDN?

[Armin Schindler]

On Tue, 19 Jul 2005, Torsten Hoefler wrote:
> Hi,
> I'm currently building an asterisk system which should work as gateway
> between SIP phones and ISDN. Most parts are working very fine, but one
> problem occurs and I am not able to solve or debug it. 
> 
> Telephony from ISDN to SIP (a Sipura Hardphone) is working very well,
> but if the SIP Phone initiates the call, the ISDN phone rings, and a
> connection can be established. But no one of the two peers can hear
> anything. 
> 
> I am using asterisk-1.0.7 with chan_capi-0.3.5, a Siemens Octopus
> Telephony System and an AVM B1 ISDN card. When I switch on debugging on
> the chan_capi, I see the packets flow? But there is still nothing to
> hear.
> 
> Do you have any suggestions? Are there any deeper (undocumented) debug
> possibilities?

This sounds like the FD bug in chan_capi-0.3.5, which happens on kernels > 
2.6.10 (AFAIR) or e.g. BSD.
Try out chan_capi-cm from sourceforge.

Armin