IP Library › Granted Patent US 4,439,634
Granted Patent Utility
US 4,439,634 · App. 06/364,820

Carrier subscriber telephone off-hook detector

Inventor: Tom L. Blackburn
Patented Case View Patent ↗
Granted: Mar 27, 1984 Filed: Apr 2, 1982
Inventor
Tom L. Blackburn
Assignee (at issue)
GTE Automatic Electric Incorporated

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Quick Facts
Patent No.
US 4,439,634
App. No.
06/364,820
Filed
1982-04-02
Granted
1984-03-27
Kind
A