03973240 is referenced by 232 patents and cites 7 patents.

A two-way communication system is disclosed utilizing power transmission lines as the transmission medium. The system is a multilevel repeater system in which each repeater has a unique address. The lowest level repeaters poll the terminal stations connected thereto in time multiplex. Transmission over the system is in the form of tone codes, each level preferably utilizing a different set of tones from the next higher or lower level.

Title
Power line access data system
Application Number
5/529998
Publication Number
3973240
Application Date
December 5, 1974
Publication Date
August 3, 1976
Inventor
Kouan Fong
Schenectady
NY, US
Agent
Jerome C Squillaro
Joseph T Cohen
Geoffrey H Krauss
Assignee
General Electric Company
NY, US
IPC
H04Q 11/00
H04M 11/04
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