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 175
ponds to the signal by throwing the answeringkeys (white) of her telephone and line No. 5 to connect the two togetherthrough any switching circuit which is not busy at the time. Learningthat No. 2 is the line desired she throws the ringing key of that line and,if ringing current is not furnished… … SUBSCRIBERS STATION EQUIPMENT 159 when the connection is established restores her answering key. Whenthe parties hang up the supervisory signal on the switching circuit willoperate and indicate that the conversation is completed. The operatorthen restores all keys to normal. On an incoming call…
Telephone
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