Video phone keep ringing after call answered


we have a GDS3710 door video unit that rings three GXV3240 phones direct via IP.
this works great EXCEPT when someone answers the call to open the door the other two phones keep ringing,
The phones themselves show no call in progress and if you pick the handset up the ringing stops till you put the handset back down then the ringing continues, The only way to stop the ringing is to reboot the phones.

We have to call direct via ip as these phones dont show the vid if they go through the asterisk system.
any ideas why this is happening



You need to do a wireshark capture.

Normally in a PBX environment, the GDS would be an extension and send an INVITE to the PBX which would then send an INVITE to the phones that need to ring. When one phone answers it sends a 200OK which then is sent back to the GDS and the call commences. Upon getting the 200OK, the PBX would then send a 487 cancel to the other phones which would cause them to stop ringing.

Not sure why you can’t handle vid, but still need a capture to understand the messaging as it seems as if there is never a cancel.