. Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems . Fig. 76.—Secondary lineswiteh, Keith. As stated in the chapter on Trunking, when the secondary line-switches are inserted between the primary lineswitches and the firstselectors, they are used to reduce the number of first selectors required,by placing the first selector switches in groups of 100 instead of in groups &witchsts in4-0 qroups ofso switches EACH 2pOO IMARY UlNET SWITCHES IN 40 GROUPS OF SO SWITCHES EACH. 3?0 TRUNKS IOO TRUNKS IOO TRUWI- <S 320 SWS. IOO FIRST IOO SECOND-SELECTORSW
. Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems . Fig. 76.—Secondary lineswiteh, Keith. As stated in the chapter on Trunking, when the secondary line-switches are inserted between the primary lineswitches and the firstselectors, they are used to reduce the number of first selectors required,by placing the first selector switches in groups of 100 instead of in groups &witchsts in4-0 qroups ofso switches EACH 2pOO IMARY UlNET SWITCHES IN 40 GROUPS OF SO SWITCHES EACH. 3?0 TRUNKS IOO TRUNKS IOO TRUWI- <S 320 SWS. IOO FIRST IOO SECOND-SELECTORSWITCHES OF-32 EACH 320 ^TRUNKS IOO TRUNI <S IOO TRUNKS 3eo secdV. LINE IOO|ROUt=SOF32 EACH IOO FIRSTSELECTORSWITCHES OOSECONOSELECTORSWITCHES Fig. 77. -Diagram illustrating scheme of using secondary lineswitches to reduce first andsecond selectors. of ten. The application of this mechanism makes it possible to give alarge number of primary lineswitches (say 2000) access to a group of 100first selectors. The drawing in Fig. 77 shows the number of primary lineswitches, thenumber of primary lineswiteh groups, the number of trunks from primary AUTOMATIC ELECTRIC COMPANYS APPARATUS 85 lineswitches to secondary lineswitches, the number of secondary lino-switch sections, the number of trunks from secondary lineswitches to firstselectors, and from first to second selectors, that might be used in a typicaloffice of 4000 lines, using third selector switches.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttelephone, bookyear19
