Patent ID: 8331352

Claim:
A method comprising: receiving, during a call between a first end device and a second end device, a SIP REFER message for the second end device to transfer the call to a third end device, wherein the first end device and the third end device communicate over the H.323 protocol, and the second end device communicates over the SIP protocol; determining interworking information to interwork the SIP REFER message with a H.323 message, wherein the determining uses a replace header in the REFER message for a consult transfer; generating a first H.323 ECS message based on the interworking information, such that the H.323 ECS message initiates the call transfer to the third end device, wherein the interworking information comprises an identifier uniquely identifying the third end device and wherein the identifier is included the first H.323 ECS message; transmitting the first H.323 ECS message to the first end device to place the first end device in a paused state; transmitting a first close logical channel (CLC) message to the first end device; transmitting a second H.323 ECS message to the third end device to place the third end device in a paused state; transmitting a second CLC message to the third end device; and establishing a call between the first end device and the third end device.