. The Bell System technical journal . inches is provided for each area codeand also one for each office code that must be translated in a particu- 874 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1952 lar C\SP, the cards representing destinations. The capacity of a singlemachine is about 1000 cards. The cards are lined up in a box as in a liUngdrawer, with tabs along the bottom of the cartl resting on select barswhich run the length of the box. One-hinidred and eighteen holes arepunched out in all cards in fixed positions so that in the normal condition118 tunnels are formed from one end to th
. The Bell System technical journal . inches is provided for each area codeand also one for each office code that must be translated in a particu- 874 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1952 lar C\SP, the cards representing destinations. The capacity of a singlemachine is about 1000 cards. The cards are lined up in a box as in a liUngdrawer, with tabs along the bottom of the cartl resting on select barswhich run the length of the box. One-hinidred and eighteen holes arepunched out in all cards in fixed positions so that in the normal condition118 tunnels are formed from one end to the other. A light source at oneend of the box shines through the tuiniels upon phototransistors (Fig. 5)at the other end but the phototransistors are disabled until, concurrentlywith the dropping of a card, voltage is applied to them. All tabs along the bottom of the card are cut off except those whichserve to identify the particular card. When a code is presented to themachine a combination of select bars corresponding to the code is. Fig. 5—Transistor. AUTOMATIC TOLL SWITCIIIXG SYSTEMS 875 lowcfcd. The caid h;i\in (hoppinj^ot the card would cnt off all lifi;ht channelshut on each card some holes luv. eniard and throufjh tliese holes thelifiht continu(>s to shine, enerf>;izinfj; the corresponding (()ml)ination of enlarged holes furnishes all of the information neededfor Iouting the call to the destination represented by the card. Fig. (3 shows the functions of th(> \ groups of tabs and designations will not appear on the actual card. Fig. 7 is a pholo-giaph of an actual card prepared foi us(v a. Sehctiiuj Tabs - Input Information. The sole use of the informationpresented to the card translator is to enable it to select the proper information presented is in the form of code digits with a
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
