Brian J Travis

US Patent:

41141415, Sep 12, 1978

Filed:

Jan 14, 1977

Appl. No.:

5/759774

Inventors:

Brian A. Travis - Sea Bright NJ

Assignee:

Datrix Corporation - Westchester NY

International Classification:

H04M 1104

US Classification:

340151

Abstract:

A communication system is disclosed for transmitting digital information between a central station and a large number of remote stations. Digital information is identified by the relationship between a simple pulse marking signal and a time reference signal which is common to all stations, that is, the time reference signal synchronizes the operation of all the stations. The relationship of the marking signal, which does not in itself carry any digital information, to the time reference signal is initially determined by the content of the digital information. Thus, this digital information can only be subsequently determined by evaluating the relationship between the marking signal and the time reference signal. In this communication system, digital radio wave transmission is used to transmit marking signals between stations and the power lines of a power distribution system are used as the source of the time reference signal. The marking signals transmitted by radio waves are used to start and stop digital counters located at each of the stations in the communication system.