Passive transmission of data over cable TV systems

A communications system which enables enhanced services to be provided over cable TV systems. The design of the system is such that amplification is not required. Therefore, two-way transmission is possible on the low band of "two-way capable" cable systems and intermediate power failures do not affect transmission. Transmission of data takes place in the low band frequency range of five to thirty megahertz. The system design is such that it can withstand over a hundred dB loss between the remote terminal and the head-end. Carrier frequencies, when received, are interleaved for purposes of decoding and microprocessor based controls are used for automatic gain control and error correction. In a preferred embodiment of the invention, two thousand five hundred carriers, each transmitting eight digital data channels of information can be simultaneously transmitted from remote terminals without any effect whatsoever on the TV signals being transmitted at the high band frequencies. The resulting system is a very economical and dependable method to achieve passive transmission of data over cable TV systems.