Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems (1921)
Smith, Arthur Bessey, b. 1875, Campbell, Wilson Lee · New York : McGraw-Hill · leaf 98
Quad-levelI RepeatersLinedank Switch-selecting IncomingRelays Selectors Fig. 74.—Plan of quad-level trunks. but the release trunks are separately attached to the private bank con-tacts. Each trunk passes through a repeater which has four relays (A-l,A-2, A-3, A-4) affected by the level selected.…
Telephone
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