W have a customer who is trying to link a CIC SIP CallCentre to the existing Mitel SX2000 voice network using a Cisco 3800 series gateway. The Mitel is connected into the Gateway using QSIG, with the CIC system using SIP to the gateway in order to call the Mitel system.
This works in part... If we make a call from the QSIG Side (Mitel) to the SIP side (CIC) then the call is established and works fine. If we make a call the other way (SIP to QSIG) it fails. The phone actually rings, but when you pick up the phone, you still hear ring tone in the originating phone, which is a signalling issue from QSIG to SIP.
If we enable debugs, we can see the message coming back from the QSIG side to say that the handset has been picked up, but we never see a similar message go out to the SIP side from the gateway.
Has anyone come across this or a similar issue before?
Any help would be appreciated.