Method for universal channel allocation based on DS-0 channelized format

This invention relates to digital communications, and in particular to channelized digital data communications over digital loop carrier wired networks. The invention has particular application in distributed digital switching systems for high-speed digital communications. A universal DS-channelized format is provided wherein selected states of CAS bits are used to indicate to the transport mechanism when DS-channels are not being used for voice and are available for use for data transport. In addition, the Tframe format carries CAS bits only in the first DS-channel, so that robbed bits are disabled and not used to carry ABCD signaling bits, thereby avoiding any risk of data corruption. Still further, a special CAS signaling value not defined as a CAS state, is employed in a frame nibble instead of a frame counter to indicate that the state is in the first DS-slot.