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 221
line < … Fig. 181.—Two different circuits of a telephone with a coin collector. response to the call the calling party is able to hear him but can not talkto him. The calling partly immediately deposits the required coin inthe coin chute, however, and as it drops to the coin box it strikes thetrigger,…
Telephone
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