Patent ID: 7072079

Claim:
In a communication system that provides a more efficient communication exchange between a first Group 3 device and a second Group 3 device, comprising: a first fax machine that generates a first message; a second fax machine that receives the first message from the second Group 3 device, generates the reply message responsive to the first message, wherein the second Group 3 device comprises: a controller that receives the first message from the first Group 3 device, recognizes the first message as coming from the first Group 3 device, and determines whether the first Group 3 device is expecting a reply message, a flag generator configured to generate a preamble comprising a series of V.21 flags, wherein the controller instructs the flag generator to generate the preamble upon determining that the first Group 3 device is expecting a reply message, and a transceiver that starts transmitting the preamble comprising the series of V.21 flags to the first Group 3 device, before receiving the reply message from the fax machine.