We are currently using a Swyx PBX which connect using SIP to a OneAccess box (which translate ISDN <-> SIP). We have trouble to make it works.
Here's the deal:
The Box uses the SIP protocol on port 5060 to communicate with the Swyx. They can handshake and we can call outside.
But when people are trying to call us, it doesn't work.
Actually, when a call comes in, the OneAccessBox try to contact the Swyx using the 5060 port but the Swyx handles the hardware phones using this port and doesn't recognize the Oneaccess as an internal phone, then it rejects the connection.
While looking at traces, it appears that the Oneaccess Box is sending a "SIP Request OPTIONS sip:_IP_OF_SWYX:65002" and the Swyx answers by an 200 OK.
While I am assuming it means that it asks the Swyx to use that port, the oneaccess keeps using 5060.
Am I assuming right that it means that "SIP Request OPTIONS sip:_IP_OF_SWYX:65002" is to use the 65002 port to handle communication?
Therefore, does this OneAccess box follows the SIP standard?
Thanks for your time.