73272364
Jul 30, 1980
Dec 8, 1981
Electronic Conference Communication Systems Consisting of Audio Units, Control Units, Receiving Units, Transmitting Units, Voting Units, and Parts Therefore and Accessories Thereto-Namely, Microphones, Headphones, Loudspeakers, Power Supplies, Plugs and Sockets, Telephone Couplers, Public Address Couplers, and Cables
Electrical and Scientific Apparatus