The Card Translator for Nationwide 

 Dialing 



By L. N. Hampton and J. B. Newsom 



(Manuscript received August 24, 1953) 



Nationwide operator and customer dialing requires the existence of a num- 

 ber of switching centers equipped with automatic systems having a much 

 higher order of mechanical ^^ Intelligence^' than previous systems. One of the 

 most important components of this new switching system is the Card Trans- 

 lator. Its function is to take the telephone address of a call and determine 

 how to advance this call toward that address. This translator has to meet 

 unique requirements in that it must accommodate a very large number of 

 addresses; must provide a great amount of information for routing the calls; 

 and must enable quick and convenient changes to be made in its stored in- 

 formation. It must also meet, of course, the normal basic requirements of 

 reliability, economy, long life, etc. The fundamental principle of this trans- 

 lator is that of a card file, containing individual coded cards for each des- 

 tination, with routing information recorded on each card. Whenever the 

 routing information for a specific code is needed, the system selects the ap- 

 propriate card, and reads the information by means of electronic circuits 

 employing phototransistors and transistor amplifiers. 



INTRODUCTION 



The "Card Translator" was developed for the 4A toll crossbar system 

 used at Control Switching Points (CSP) in the nationwide dialing net- 

 work of offices. Although the many problems and conditions presented 

 in the development and implementation of a nationwide dialing plan 

 have been discussed in papers* by A. B. Clark, J. J. Pilliod, H. S. Os- 

 borne, W. H. Nunn, F. F. Shipley and others, it is necessary to restate 

 some of these because of their effect on the translation problem and the 

 features the card translator had to have in order to meet the nationwide 

 dialing requirements. Translation is the process of converting the called 

 destination code into information that is needed for the proper routing 

 of the call. 



* B.S.T.J., 31, pp. 823-882, Sept., 1952. 



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