DSL access system negotiating a voice codec type to be used between two systems

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 (DSLAM) 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,
• wherein the multiplexer transmits encoded voice data in a 16/8 kbps channel through the DSLAM to the gateway unit using the voice coding technique,
• wherein the gateway unit is configured to decode encoded voice data from the 16/8 kbps channel to a decoded 64 kbps channel containing decoded voice data and the gateway unit inserts the encoded voice data into the least significant bits of the decoded 64 kbps channel, and
• wherein the gateway unit transmits both encoded and decoded voice data to the second system by combining a TFO protocol on the encoded 16/8 kbps channel and a non-TFO protocol on the decoded 64 kbps into a channel transmitted to the second system such that both the TFO protocol and the non-TFO protocol are available to the second system.

A method for connecting a subscriber device to a digital subscriber line through an integrated access device to communicate voice packets, the method comprising:

• determining if a peer entity supports tandem free operation (TFO), and if the peer entity supports TFO:
• identifying a voice codec being used by the peer entity;
• encoding voice packets according to the identified voice codec;
• and
• transmitting encoded voice packets in a 8/16 kbps channel to a gateway unit through a digital subscriber line access multiplexer (DSLAM);
• decoding encoded voice packets from the 8/16 kbps channel into a decoded 64 kbps channel containing decoded voice packets;
• inserting encoded voice packets from the 8/16 kbps channel into the least significant bits of the decoded 64 kbps channel;
• and
• transmitting both encoded and decoded voice packets to the peer entity, wherein the gateway unit combines a TFO protocol on the 8/16 kbps channel and a non-TFO protocol on the decoded 64 kbps channel into a channel having both the encoded and decoded voice packets transmitted to the peer entity, such that both the TFO protocol and the non-TFO protocol are available to the peer entity.