Two-way cable-television system

A tree-type two-way data communications system for use in a cable televison system having a single head-end subsystem, a plurality of data sources and a cable television distribution network wherein each said data source is a source of digital commands to said head-end subsystem, said two-way system comprising:

• a plurality of interface subsystems intermediate of said head-end subsystem and each one of said data sources, said interface subsystems being coupled in a tree structure to said head-end subsystem, each one of said data sources being coupled to one of said interface subsystems, and each one of said interface subsystems being coupled to at least one other of said interface subsystems, said interface subsystems receiving without acknowledgment through said cable distribution network from at least one of said data sources said digital command signals, each said interface subsystem verifying data for mat and regenerating and forwarding at least some of said digital commands as command packet signals in a packet signal format on an uplinked carrier towards said head-end subsystem;
• said head-end subsystems receiving said digital command signals as said command packet signals and developing response signals;
• and
• said cable-distribution subsystem coupling response signals in a tree-structure without loops from said head-end subsystems to each one of said data sources through a common signal path independent of said uplink for acknowledging receipt of said command packet signals.