Added bit signalling in a telecommunications system

Claim 1

In a telecommunications system including a conventional telephone network and a passive distribution network, the conventional telephone network employing a signal format comprised of frames, each frame comprised of a group of n-bit channel samples and at least one framing bit, the framing bit of each frame having an associated location and state such that a plurality of the framing bits in a succession of frames define multiframe and alignment information, and wherein the passive distribution network connects a head end and a plurality of remote ends, the passive distribution network employing a modified signal format comprised of modified frames, each modified frame not including the framing bit, a system for transmitting the multiflame and alignment information between the head end and the remote ends, comprising: an input circuit in the head end connected to receive the frames from the conventional telephone network; a framing bit monitoring circuit adapted to determine the location and state of the plurality of flaming bits in the received flames to determine the multiframe and alignment information for the received frames; an added-bit generator under control of the framing bit monitoring circuit and adapted to output a sequence of bits having a preselected pattern imposed thereon in an alignment controlled by the location and state of the plurality of framing bits, wherein the preselected pattern is representative of the multiframe and alignment information; and a multiplexor, connected to receive the n-bit channel samples of the received frames from the flaming bit monitoring circuit and the sequence of bits from the added-bit generator, and having an output signal comprised of the modified frames of the modified signal format, each modified frame comprised of a group of modified channel samples, each modified channel sample comprised of an n-bit channel sample having at least one bit of said sequence of bits appended thereto.

Claim 12

A method of conveying signalling information in a communications system comprised of a central office which outputs communication signals employing a signal format comprised of a plurality of frames, each frame comprised of a plurality of channel samples and a framing bit, the framing bit of each frame having an associated location and state such that a plurality of framing bits in a succession of frames have signalling information encoded therein, the communications system further comprised of a head end and a plurality of remote ends, comprising the steps of: (a) receiving the plurality of frames at the head end from the central office; (b) monitoring the location and state of each framing bit in the received plurality of frames; (c) generating a series of bits in one of a plurality of signalling patterns, each signalling pattern representative of signalling information; (d) extracting the plurality of framing bits from the plurality of frames: (e) sequentially appending, according to the location and state of the framing bit, at least one bit in the series of bits to each channel sample to create modified channel samples; (f) routing each of the modified channel samples from the head end to the respective remote ends; (g) receiving the modified channel samples at the remote ends; and (h) monitoring the signalling pattern at the remote ends to locate the signalling information.

Claim 13

A method of conveying signalling information in a communications system comprised of a central office which outputs communication signals employing a signal format comprised of a plurality of frames, each frame comprised of a plurality of channel samples and a framing bit, the framing bit of each frame having an associated location and state such that a plurality of framing bits in a succession of frames have signalling information encoded therein, the communications system further comprised of a head end and a plurality of remote ends, comprising the steps of: (a) receiving the plurality of frames at the head end from the central office; (b) monitoring the location and state of each framing bit in the received plurality of frames; (c) generating a series of bits in one of a plurality of signalling patterns, each signalling pattern representative of signalling information; (d) extracting the plurality of framing bits from the plurality of frames: (e) sequentially appending, according to the location and state of the framing bit, at least one bit in the series of bits to each channel sample to create modified channel samples; (f) routing each of the modified channel samples from the head end to the respective remote ends; (g) receiving the modified channel samples at the remote ends; and (h) monitoring the signalling pattern at the remote ends to locate the signalling information.