System and method for multiplexing fractional TDM frames

A communication system comprising:

• a plurality of end user devices having a time division multiplex (TDM) port;
• a plurality of remote units having a TDM port, the TDM port in each of the plurality of remote units coupled to the TDM port in one of the plurality of end user devices,
• a plurality of central units having a TDM port, each of the plurality of central units coupled to one of the plurality of remote units via a digital subscriber line (DSL) link, wherein each remote unit is operable to transport, over the DSL link to the corresponding central unit, a fractional TDM frame received from the corresponding end user device;
• a networking device to transmit and receive TDM frames, wherein the maximum number of available timeslots in each of the TDM frames transmitted and received by the network device is equal to the maximum number of available timeslots in each of the fractional TDM frames;
• and
• a multiplexing card having a primary TDM port coupled to the networking device and a plurality of secondary TDM ports each coupled to the TDM port in one of the plurality of central units, wherein the multiplexing card is operable to map timeslots from each of the fractional TDM frames received from the plurality of central units to corresponding timeslots in a TDM frame transmitted over the primary TDM port to the networking device, and to map each of a plurality of blocks of timeslots in a TDM frame received over the primary TDM port from the networking device to corresponding timeslots in a fractional TDM frame transmitted over one of the plurality of secondary TDM ports to one of the plurality of central units;
• wherein the combined number of timeslots mapped from the plurality of fractional TDM frames is less than or equal to the maximum number of available timeslots in the corresponding TDM frame transmitted over the primary TDM port;
• wherein the multiplexing card is further configured to buffer and map signaling information in a respective Channel Associated Signaling (CAS) timeslot from each of the fractional TDM frames received over the plurality of secondary TDM ports to a single CAS timeslot in the corresponding TDM frame communicated over the primary TDM port based, at least in part, on the mapping of timeslots containing user data between the fractional TDM frames and the TDM frame communicated over the primary TDM port.

A method of communicating fractional TDM frames, the method comprising:

• transmitting a fractional TDM frame from each of a plurality of end user devices to a corresponding remote unit;
• transporting the fractional TDM frame received at each remote unit in a digital subscriber line (DSL) frame over a DSL link to a corresponding central unit;
• extracting the fractional TDM frame from the DSL frame at each central unit;
• providing the extracted fractional TDM frame from each central unit to a multiplexing card;
• mapping a subset of timeslots from each of the fractional TDM frames to corresponding timeslots in a single TDM frame in the multiplexing card, the subset of timeslots from each fractional TDM frame being less than the total number of available timeslots for the respective fractional TDM frame, wherein the total number of available timeslots in each of the fractional TDM frames is equal to the total number of available timeslots in the single TDM frame;
• and
• providing the single TDM frame to a networking device;
• wherein mapping the subset of timeslots from each of the fractional TDM frames includes buffering and mapping signaling information in a respective Channel Associated Signaling (CAS) timeslot from each of the fractional TDM frames to a single CAS timeslot in the corresponding single TDM frame based, at least in part, on mapping timeslots containing user data from the fractional TDM frames to the single TDM frame.