Patent ID: 8340118

Claim:
A multiplexing card for fractional time division multiplex (TDM) frames, the multiplexing card comprising: a primary TDM port over which TDM frames are communicated to and from a networking device, a plurality of secondary TDM ports over each of which fractional TDM frames are communicated to and from a plurality of digital subscriber line (DSL) units, wherein the maximum number of available timeslots in each of the fractional TDM frames is equal to the maximum number of available timeslots in the TDM frame communicated over the primary TDM port; and a logic device coupled between the primary TDM port and the plurality of secondary TDM ports, wherein the logic device is operable to map timeslots from each of the fractional TDM frames received over the plurality of secondary TDM ports to corresponding timeslots in a TDM frame communicated over the primary TDM port, and to map each of a plurality of blocks of timeslots in a TDM frame received over the primary TDM port to timeslots in a corresponding fractional TDM frame transmitted over one of the plurality of secondary TDM ports; wherein the combined number of timeslots containing user data in the fractional TDM frames received over the plurality of secondary TDM ports is less than or equal to the maximum number of available timeslots in the corresponding TDM frame communicated over the primary TDM port; wherein the logic device 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.