customer use our AR1220 to work with third-party PBX, and AR is PBX itself.the outgoing call from AR sip user to remote extension(under third-party device) is ok, but AR don't response the incoming call from remote even AR have received the incoming signaling.
the topology is as following.
phone c register to AR (192.168.76.2), phone A and B belong to remote site TSP. there is a SIP trunk between TSP sit(93.*.*.34) and AR(10.*.*.5).
C make an outgoing call to A or B, work ok.
A make an incoming call to C, call fail.