Fax problem maybe due to CRC error for HDLC?

Hi,

I’m experiencing frequent FAX errors on an analog fax connected to an IAXy. Problem is mostly incomplete faxes (1/2 page or errors leading to disconnect). Errors occur on incoming and outgoing faxes.

The IAXy is connected to an asterisk which is connected with quadBRI to 2 ISDN BRI interfaces.

Since I also get errors in syslog (below), maybe they have to do something with the fax problems?
Oct 4 19:18:53 pbx kernel: qozap: CRC error for HDLC frame on card 1 (cardID 0) S/T port 1
Oct 4 19:21:27 pbx kernel: qozap: CRC error for HDLC frame on card 1 (cardID 0) S/T port 2

These ports are the ISDN ports that are being used. The errors occur about every 1 minute in syslog.

The zaptel.conf looks like this:
span=1,1,3,ccs,ami
span=2,0,3,ccs,ami
span=3,0,3,ccs,ami
span=4,0,3,ccs,ami

bchan=1,2
dchan=3
bchan=4,5
dchan=6
bchan=7,8
dchan=9
bchan=10,11
dchan=12

Oh, if it’s important, region is Belgium. And asterisk being used is BRIstuff 0.3.0-PRE-1y-j. (* 1.2.23, libpri 1.2.4, zaptel 1.2.19)

I would appreciate any advice or pointers on this one…

cheers,
stoffell