Patent ID: 7614074

Claim:
A cable television system for transmitting forward and reverse signals, the cable television system comprising a communications system comprising: a plurality of optical nodes including a reverse optical transmitter, each optical node for receiving reverse analog electrical signals modulated onto radio frequency (RF) carriers from a plurality of subscriber equipment and for providing reverse digital optical signals, each reverse optical transmitter comprising: a converter for converting the reverse analog electrical signals into digitized electrical reverse signals; a RF carrier-detect circuit coupled to the converter for monitoring at least one of an input of the converter and an output of the converter, the RF carrier detect circuit providing a control signal in response to detecting the presence of a RF carrier signal in the reverse analog electrical signals; a delay circuit coupled to the converter for delaying the digitized electrical reverse signals provided by the converter; a switch coupled to receive the delayed digitized electrical reverse signals provided by the delay circuit, the switch being controlled by the RF carrier-detect circuit for selectively connecting the reverse optical transmitter with a digital network such that the reverse optical transmitter transmits the reverse digital optical signals upstream through the digital network only if the carrier-detect circuit detects the presence of the RF carrier signal in the reverse analog electrical signals; and a reverse optical receiver, coupled to the plurality of optical nodes via the digital network, for receiving and passively combining the reverse digital optical signals from each of the plurality of optical nodes.