Call Manager 4.x (skinny) (extensions 222x) with h.323 gw (2811)
Trixbox 2.6 (sip) (extensions 333x) with sip trunk (2811)
Also on the 2811 is a PRI from the pstn.
A call from a trixbox phone to a call manager phone rings the phone, but once you pick up the headset on the call manager phone the call continues to ring on the trixbox phone and eventually says "all circuits are busy"
We are able to make calls from the call manager phone to a trixbox phone with no issues. We are also able to make inbound & outbound calls to / from the pstn to both the cisco call manager phones and the trixbox phones.
We have ran debugs on the 2811 router and confirmed the correct dialpeers are being hit when calling to and from ccm / tbox.
We have also put a sniffer on the network and found the cisco phone sends and acknowledgement of the pickup back to ccm and then the communication stops.