TRANSLATORS AND IDENTIFIERS IN SWITCHING SYSTEMS 625 



unit and in some patent literature the term "calling line identifier" is ac- 

 tually used. In practice this number is later used as an input to a translator 

 (Fig. 7) to obtain the calling directory number. Any relay not serving merely 

 as a means to renew or register a signal acts as the coding element of a tians- 

 lator or identifier. 



Finally it looks to the writer as if any of the units made up of numerous 

 relays, or other devices, as used in common control systems, act like trans- 

 lators with a vast number of possible input and output con^binations with 

 the action resulting from the output codes often fed back as part of a new 

 input code. 



There might then be considerable possibiHty that any fundamental im- 

 provement in general switching network theory or in the theory of trans- 

 lators and identifiers would be of mutual advantage. 



Acknowledgements 



The author wishes to express his appreciation to Messrs. O. A. Friend, 

 O. Myers and R. Marino, of the Bell Telephone Laboratories, for their 

 assistance in the work on this paper. 



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