TRANSLATORS AND IDENTIFIERS IN SWITCHING SYSTEMS 609 



when dealing with a translation problem with a new approach, and also 

 some which must be considered. These and other possible variations will 

 be reviewed later. 



Slide Bar Translator 



This proposed device was the forerunner of one of the Bell System's most 

 important projected translators and is worth examining for the new princi- 

 ples.® 



In this case, as in the cross-reference system just described, one of the 

 objectives was reduction in cost by eliminating the separate equipment 

 for selecting the coding elements and combining the selecting equipment as 

 far as possible with the coding equipment. A further purpose was to provide 

 non-electrical coding elements with improved tractability for making 

 changes. 



The construction of this device is shown in Fig. 9. The coding elements 

 consist of thin slide bars shown in Fig. 9(a), each notched in accordance 

 with the input code on one end and the output code on the other. These 

 are stacked as shown in Fig. 9(d). The selecting equipment is a combination 

 of code bars, Fig. 9(b), which work in combination with the wide and 

 narrow notches of the slide bars, so that when a combination of select code 

 bars is operated according to an input code all slide bars except the one 

 carrying the input code are restrained from sliding when the common 

 operating magnet is actuated. The one slide bar slides to the right, this 

 representing the selection of the coding element. 



The reading code bars are now all operated and only the set corresponding 

 to the output code of the displaced slide bar can operate fully. Contacts 

 on the output code bars then mark the output code leads. 



Because this device is slow relative to relay or electronic translators 

 owing to its mechanical elements, it has limited traffic capacity and would 

 have to be duplicated many times in each office. Its advantage, however, 

 lies in the fact that, when changes in translation are to be made, new coding 

 elements (slide bars) can be prepared in advance and the changes made 

 simply by substituting the new bars for the old, without changing cross 

 connections. 



Card Translator 



While the slide bar translator is sometimes spoken of as a "card trans- 

 lator" it is similar to but by no means the same as the card translator which 

 the Bell System proposes to adopt for toll crossbar offices. 



« See U. S. Patent /j^ 2,361,246 issued to Mr. George K. Stibitz. 



