-
-
Video observation systems
-
Patent number 4,876,597
-
Issue date Oct 24, 1989
-
ADT Security Systems, Inc.
-
Bernard J. J. Roy
-
H04 - ELECTRIC COMMUNICATION TECHNIQUE
-
Remote video observation systems
-
Patent number 4,843,462
-
Issue date Jun 27, 1989
-
ADT Security Systems, Inc.
-
Bernard J. J. Roy
-
H04 - ELECTRIC COMMUNICATION TECHNIQUE
-
-
Power line signalling system
-
Patent number 4,245,215
-
Issue date Jan 13, 1981
-
American District Telegraph Company
-
Lorne D. O'Connor
-
H04 - ELECTRIC COMMUNICATION TECHNIQUE