File:Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems (1921) (14753940664).jpg

Identifier: automatictelepho00smit (find matches)
Title: Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems
Year: 1921 (1920s)
Authors: Smith, Arthur Bessey, b. 1875 Campbell, Wilson Lee
Subjects: Telephone
Publisher: New York : McGraw-Hill
Contributing Library: University of California Libraries
Digitizing Sponsor: Internet Archive

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tive terminal of the battery. It thereforebecomes necessary to add the 430-ohm resistance coil X to the connectorswitch and to make some slight alterations in the circuit. Since, other-wise, it is practically the same as that shown and described in Chapter III,only the operation- in connection with the manual switchboard will beexplained here. It will be noted that the positive side of the connector-bank multipleis connected directly to the tip side of the manual switchboard multiple,the negative side of the connector bank is connected to the ring side ofthe manual-switchboard multiple, and the corresponding private contactsof the connector bank are connected to the sleeve multiple of the manualswitchboard. The result is that whenever the connector switchcompletes connection to any line, the sleeves of all the correspondingjacks and the private bank contacts are connected to negative battery,through the private wiper, make-springs relay W and resistance coil X. 332 AUTOMATIC TELEPHONY
Text Appearing After Image:
CUT-OVERS AND INTERCONNECTING OFFICES 333 On the other hand, whenever a connector switch finds a line made busy,in one of its jack, in the manual switchboard, a circuit may be tracedfrom negative battery of the manual switchboard, through the lamp andcontact of cord relay B, resistance coil 2, the sleeve of the plug, the sleeveof the jack, the private bank multiple, private wiper, break-springsrelay W, make-springs relay A (relay A has not yet de-energized, follow-ing the rotary impulses), break-springs relay W, busy relay B to positivebattery. The result is that the busy relay closes a circuit from thebusy bus bar to the positive side of the calling subscribers loop, at thesame time closing a locking circuit for itself which may be traced fromground, relay B, break-springs relay W, break-springs relay A (which bythis time has de-energized), make-springs relay B, resistance X to nega-tive battery. Thus it will be seen that the calling subscriber will con-tinue to receive the busy tone

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