Abstract: A bidirectional cable communication system comprising a head and, a bidirectional transmission network connected to the head end for transmitting signals downstream from the head end to a plurality of subscriber stations and for transmitting data signals upstream to the head end from the subscriber stations, means at the head end for detecting collisions between signals received from the subscriber stations and for generating a collision signal, means at the head end for transmitting downstream on the transmission system status bits of data signal indicative of the collision, whereby upon detection thereof by a subscriber station it can be enabled to cease transmission.

Abstract: A system for providing television, information and data signals via a transmission network to selected subscribers, to groups of subscribers, or to all subscribers connected in common to the transmission network. An address code signal is stored at the subscriber station, and an option code signal is sent to the particular subscriber station from a head end of the network. Signals having an address portion designative of the option code or address code signal are sent down the transmission line and are translated by the subscriber station in the event the address matches the first and second code signal. Thus signals can be sent to all subscribers which have option codes designated by the address of data packets transmitted down the transmission line. These groups of subscribers can be all subscribers, individual smaller groups of subscribers, or a group consisting of even a single subscriber. The option codes can be changed from the head end at will.