Hello all, trying the zaphfc driver from Klaus-Peter Junghanns with Cologne-Chip PCI card I experience a clearly audible crackling sound during calls through the Zap BRI channel to PSTN. Calling the same destination from the same SIP extension via sipgate.de the sound is perfect. What I hear sounds like massive pattern slipping on the BRI. The channel used is the primary clock source. I have 'echocancel=no' (also tried 'yes') in zapata.conf und this in zaptel.conf: # PSTN DTAG span=1,1,3,ccs,ami bchan=1-2 dchan=3 Help is greatly appreciated because faxing is terribly impossible right now. Thank you and king regards, Jan Baumann