We have the following scenario: Two Cisco routers (one 2610 and one 7206) connected via Frame Relay between them, and each router has a PRI - QSIG (using NM-HDV-1E1 card) connection on a SIEMENS HICOM 300H PBX. Everything works fine (all the features of the PBX pass through to the other side), EXCEPT the CALL-BACK feature. I have captured traces for debug isdn q931 on both routers, and I noticed that when the callback request is made from the PBX, the debugging shows "Cause i = 0x80A2 - No circuit/channel available".
Note again that ALL other features (conferencing, transfer, name display etc) pass through without problems. Another thing to consider is that we are using VOIP dial-peers with dtmf-relay h245-alphaneumeric enabled.
Does anyone encountered similar problems before.
thank you very much