. American telephone practice . al position the off-normal switch will be open, while assoon as the shaft is moved upward one step or any number of stepsthe off-normal switch will be closed and a lamp common to a groupof switches be lighted, if the small hand switch, 26, is closed. Theobject of this is to afford facility for the detection of any switch orswitches in a group which may be, through some fault in the work-ing of the system, left in other than normal position. At / isshown a constantly driven interrupter, the purpose of which is toafford to the rotary magnet periodically recurring
. American telephone practice . al position the off-normal switch will be open, while assoon as the shaft is moved upward one step or any number of stepsthe off-normal switch will be closed and a lamp common to a groupof switches be lighted, if the small hand switch, 26, is closed. Theobject of this is to afford facility for the detection of any switch orswitches in a group which may be, through some fault in the work-ing of the system, left in other than normal position. At / isshown a constantly driven interrupter, the purpose of which is toafford to the rotary magnet periodically recurring current impulsesfrom the battery, B, during the time while the side switch is in itssecond position. AUTOMATIC SWITCH-BOARD SYSTEMS. Ill Before passing to the operation of the selector switches under thevarious circuit conditions, attention should be called to the fact that FIG. Ck SCHEMATIC CIRCUIT BEFORE ee<3lHMlM<* FIRST SELECTOR. CALLING. CALLING, rmarr selector substatioh TO £E CALLEp. TO EiE
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Keywords: ., boo, bookcentury1900, bookdecade1900, bookidamericantelepho00mill
