Hello - This problem has dogged me for weeks now. I have installed the latest Asterisk (1.4.9), libpri 1.4.1, zaptel 1.4.4 - and the TRUNK version of chan-capi. also the HEAD version - all compiled well under CentOs 5.0 - and it works with IAX soft phones properly. However, when I call from an ISDN phone through chan_capi to asterisk - I hear no PlayBack MusiconHold is violent data stream noise I can hear what is said into the phone in the softphone but in ISDN I hear noise, or nothing. dialing in and out - no problem. I have tried many things - the 1.2 branch of Asterisk and all else, the HEAD version of chan_capi, stable - all of them. but still the problem remains. I have also tried several versions of the C4 firmware - no difference. This card was working on a PII 2 CPU machine and a much earlier version of asterisk and chan-capi. any ideas? My new machine is a Dual core Pentium 4300 w/ 4gb RAM. Very fast, stable, but it can not go into production until this is fixed! thank you - ?lainn ***************************************************************************** "The cheese-mites asked how the cheese got there, And warmly debated the matter; The orthodox said that it came from the air, And the heretics said from the platter." Anon.