. Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems . JprckonToll r=, Ji—i-board Q Fig. 249.—Toll selector. real third selector or not depends upon the size of the exchange. Inany case this is the switch which feeds battery to the called switch functions as an ordinary selector, except that the oper-ating relay OpRy takes the place of the usual line relay and is controlled LONG DISTANCE AND SUBURBAN EQUIPMENT 293 over the operating trunk, P-l. The talking circuit, indicated by theheavy lines, is entirely separate from the rest of the selector.
. Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems . JprckonToll r=, Ji—i-board Q Fig. 249.—Toll selector. real third selector or not depends upon the size of the exchange. Inany case this is the switch which feeds battery to the called switch functions as an ordinary selector, except that the oper-ating relay OpRy takes the place of the usual line relay and is controlled LONG DISTANCE AND SUBURBAN EQUIPMENT 293 over the operating trunk, P-l. The talking circuit, indicated by theheavy lines, is entirely separate from the rest of the selector. When a connection has been extended to this switch, the operatingrelay OpRy is energized and in turn pulls up the release relay RlRy. Therelease relay grounds the release trunk P-2 so as to hold the switchesback of it in the operated position, opens the release circuit to the releasemagnet Rise, and prepares the circuit to the vertical magnet Fig. 250.—Toll third selector (transmission selector). At each interruption of the calling device in the sleeve of the toll cord,the line relay drops back and operates the vertical magnet in series withthe series relay SeRy through a back contact on the switching relay SwRy,and a front contact on the release relay. The off-normal springs close on the first vertical step, preparing therelease circuit and closing a circuit for the interrupter relay IR throughthe front contact of the series relay SeRy to release trunk ground. Theinterrupter relay pulls up and locks itself to the ground at the operatingrelay (front contact) which at the end of the group of impulses will besteady. The interrupter relay prepares a circuit for the rotary magnet. 294 AUTOMATIC TELEPHONY When the impulses cease, the operating relay comes to rest series relay drops back and closes the circuit of the rotary magnet torelease trunk ground. The rotary magnet pulls the wipers onto the firsttrunk in t
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttelephone, bookyear19
