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 38
Csection of second selectors in the third thousand (second office). The Cand D first selectors in the first office have a different group of ten trunksto the same third thousand (section D of second selectors). If the twooffices have five complete thousands each, it takes five such groups often… … lOTrks lOTrks IQTrks lOTrks
Telephone
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