Patent ID: 7872773

Claim:
A method for ensuring reliable transmission of a Disconnect (DCN) signal to a facsimile machine by a T.38 gateway, comprising: detecting, by the gateway, frame signals demodulated and received on a Time Division Multiplexing (TDM) side, and packing, by the gateway, a DCN signal for a facsimile into an IP Fax Protocol (IFP) packet and sending the IFP packet to an Internet Protocol (IP) side when the DCN signal is detected; reporting, by the gateway, a fax end event to a Soft Switch after a designated delay period, after packing the DCN signal and sending the packed DCN signal to the IP side, wherein the designated period is a period required to ensure that the integral DCN signal reaches a receiving facsimile machine; and receiving a State Switching Command and switching from Fax state back to voice state by the gateway.