Patent ID: 7626976

Claim:
A digital subscriber line (DSL) access system comprising: a multiplexer for connecting a subscriber device to a digital subscriber line; a digital subscriber line access multiplexer (DLSAM) for connecting the digital subscriber line to a backbone network; and a gateway unit for connecting the backbone network to a second system wherein the DSL access system is configured to apply a voice coding technique between the gateway unit and the subscriber device or the multiplexer for a voice call communicating wherein, when the access system transmits a voice call between the subscriber device and the second system employing voice coding, the access system is configured to use a TFO (Tandem Free Operation) protocol on a first communication channel and configured to use a non-TFO protocol on a second communication channel, wherein the first communication channel comprises an encoded 8/16 kbps channel and the gateway is configured to receive said first communication channel and to generate a corresponding decoded 64 kbps channel, and the second communication channel comprises the decoded 64 kbps channel, and wherein the gateway unit is configured to combine the first and second communication channels into a third channel and present the third channel to the second system such that both the TFO protocol and the non-TFO protocol are available to the second system.