04450481 is referenced by 185 patents and cites 10 patents.

An expandable, multipurpose digital and analog communications system in which a plurality of remote interrogator units connected in a branch of the system are isolated from one another by band stop filters to permit simultaneous polling without interference with other operations. Also disclosed is a premium service control unit which makes uses of a frequency agile oscillator.

Title
Tamper-resistant, expandable communications system
Application Number
6/296171
Publication Number
4450481
Application Date
August 25, 1981
Publication Date
May 22, 1984
Inventor
Robert V C Dickinson
Berkeley Heights
NJ, US
Agent
George E Kersey
Assignee
E Com Corporation
PA, US
IPC
H04N 7/10
H04N 7/16
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