Abstract: A system for transmitting and receiving digital data which utilizes pre-coding at a transmitter, and selects post-coding at a receiver when co-channel interference not present or post-comb processing at the receiver when co-channel interference is present. The system includes a symbol interleaver at the transmitter and a symbol deinterleaver at the receiver which minimizes the byte errors by organizing the data input at the pre-coder at the transmitter such that the symbol errors and their respective propagated errors are re-organized so as to be disposed adjacent to each other, thereby forming adjacent symbol errors. The effect of this re-organization is to increase the probability that each pair of adjacent symbol errors correspond to bits which lie in the same byte.

Abstract: An interactive cable network for sending information to, and receiving information from a plurality of subscribers. The information is sent from a head-end through a central distributor which includes a plurality of head-end modems each capable of transmitting information at respective transmit frequencies within a first range of frequencies, and receiving information at respective receive frequencies within a second range of frequencies. The respective transmit and receive frequencies for each head-end modem form a respective modem frequency pair. Each head-end modem is coupled to a group of user modems and each respective user modem of each group operates on the respective modem frequency pair of its respective head-end modem. The central distributor also interrogates each user modem within each group of user modems.