I have an existing PBX that does not speak SIP. This PBX is connected to two PRI's that all are existing extensions are on. The PBX does speak MGCP and H323. Is it possible to use a Cisco 2811 with DSP's installed as a gateway to route calls from the PBX to the router and then from the router to my Asterisk/Trixbox server for my SIP phones ? Any suggestions on whether I should use H323 or MGCP between the PBX and router ? Does the router have the capability to receive H323 or MGCP, convert this to SIP , and send it to my Asterisk/Trixbox server ? Thanks.