No Audio asterisk to sip phone when wcfxs loaded


If I type in:

modprobe -r wcfxs

I can get audio on SIP channels.

If I type in

modprobe wcfxs

I can no longer get audio. asterisk says it is playing the required
audio files but I cannot see any RTP packets being sent, using tcpdump,
tethereal or strace.

(note: asterisk is not configured to use the Zap channels).

If I look up status information in asterisk, it sees it has received
thousands of RTP packets, but only sent 1.

Talking between SPI phones also works.

I have also made extensive web searchs on the topic, but not been able
to find any solutions. I have found other people with similar problems

I have a TDM400p adaptor. I am not using NAT in anyway shape or form
(all systems are on a private network and have IP addresses).

Any ideas?

I was kind of hoping that ZAP and SIP wouldn’t be mutually exclusive…



Seems like it was a problem with the motherboard.

Same I/O card, same harddisk, different computer, works fine.

Thanks to tzafrir (IRC) for helping me.

Apparently interrrupts weren’t getting through, which messed the timing source.