i'm faced with a strange one way audio problem while integrating siemens pbx with a cisco voice gateway. they are connected through an E1 Qsig and the voice gateway (2821)is configured as H323 on the call manager (7.0). The call passes through when calling from an Cisco ip phone to a siemens PBX however nothing is heard when calling from a Siemens to a Cisco ip phone.
the strange thing about it, is that sometimes it works sometimes it doesn't.
siemens phone-->siemens PBX(hipath 4000)-->voice gateway-->UCM 7.0-->Cisco IP phone
Anyone has an idea about what could be the problem?
thanks in advance,