73216958
May 24, 1979
Apr 7, 1981
Intercom and Other Electronic Adjuncts for Use in Connection with a Business Telephone System-Namely, Station Expanders, Lamp Flashers, Link Expanders, Off-Premise Adaptors and Busy Signal Indicators, Dial Repeating Line Units, Conference Call Units, Paging Adaptors, and Ring-Down Line Units
Electrical and Scientific Apparatus