AUTOMATIC TOLL SWITCIIIXG SYSTEMS 875 



lowcfcd. 'The caid h;i\in<i all tat)s cul oil' excel)! those restiiij:,- on the 

 lo\\(M('(l hars will (irop hut all other cards will remain in place, if nothinj; 

 fuithei- were done th(> (h'oppinj^ot' the card would cnt off all lifi;ht channels 

 hut on each card some holes luv. eniar<i;(>d and throufjh tliese holes the 

 lifiht continu(>s to shine, enerf>;izinfj; the corresponding pliototi'ansistors. 

 The ('()ml)ination of enlarged holes furnishes all of the information needed 

 for I'outing the call to the destination represented by the card. 



Fig. (3 shows the functions of th(> \-ariou.s groups of tabs and holes. 

 The designations will not appear on the actual card. Fig. 7 is a pholo- 

 gi'aph of an actual card prepared foi' us(v 



a. Seh'ctiiuj Tabs - Input Information. The sole use of the information 

 presented to the card translator is to enable it to select the proper card. 

 The information presented is in the form of code digits with accompan}^- 

 ing indications of their nature. The information is recognized by cutting 

 off tabs along the bottom of the card in proper combinations. 



The groups of tabs labeled A, B, C, D, E and F are for the six code 

 digits. For each digit used two tabs are left since the digits are registered 

 in the sender on a two-out-of-five basis and the leads from the sender 

 will operate the select bars directly. If the card represents an ordinaiy 

 three-digit code all tabs will be cut off except two each of the A, B and C 

 tabs, two of the four CG tabs and perhaps either the VO or NVO tab. 

 The CG (card group) tabs are used in combination to indicate three- 

 digit, six-digit and alternate route card groups. The VO and NVO (via 

 only and not via only) tabs are used when the group of toll lines over 

 which the call will be routed is divided into one subgroup of a trans- 

 mission gi-ade suitable for only terminal traffic and another subgroup 

 for either terminal or switched traffic. If the card represents an ordinary 

 six-digit code two tabs will be left in each of the digit posiTions, and a 

 different pair in the CG group. 



h. Punch Holes -Output Information. The output information from 

 the card translator is recognized in the decoder and marker by relays 

 operated in the combinations set up by enlargement of associated holes 

 in the card. The output from the phototransistors is amplified by other 

 transistors to fire cold cathode tubes which in turn operate the relays. 



The pretranslation group on the top line of Fig. 7 indicates how 

 many digits the sender must supply for a complete translation. The 

 term ''pretranslation" implies that fvu'ther translation is reciuired. This 

 is not always true. In many ca.ses only the first three digits need to be 

 translated and all information needed for routing the call is supplied by 

 this card. In many cases the six digits of the area and office code are 

 needed and the routing information will be on another card to be selected 



