612 THE BELL SYSTEM TECHNICAL JOURNAL, JULY 1951 



practical if only a few more output codes were required because of the great 

 increase in the number of permutations. 



General Thoughts on Translators 



Broad Considerations in Choosing Translation System 



If a switching system designer were confronted with the problem of 

 providing a large scale translator and he were given full latitude, there 

 would be many factors he would have to consider and a wide variety of 

 choices he could make in order to reach the most economical and useful 

 design, even if he were uninventive and restricted to the combinations of 

 the present art. Actually he would not have full latitude, for the translator 

 design must always be coordinated with the design of other elements and 

 often is subordinated or greatly limited by the importance of the more 

 intricate or costly elements with which the translator must work. The best 

 he can do is to arrange his design to help provide the most economical and 

 serviceable system from an overall standpoint, and in this the translator 

 design might not be ideal. 



What are some of the more important factors that the designer can 

 juggle and what choices can be made within the known possibilities? 



Let us assume that the problem specifies, for some new type of common 

 control ofl&ce, large scale translation between equipment and directory 

 numbers in both directions. Then the following decisions are certainly 

 important: 



(1) One-way or Two-way Operation? » 



This is determined by economic study if the available two-way 

 translators are satisfactory. 



(2) Should translators be provided for each circuit requiring their use 

 or should they be provided for access to circuits in common? 



This can be determined only be economic studies. 



(3) If the translation system is to be common, should it be based on the 

 use of a single full-capacity translator or numerous smaller trans- 

 lators involving more translator connecting devices? 



This involves economic studies and questions of the speed or 

 traffic capacity of the translator and the question of relative 

 service hazards in the two arrangements. 



(4) What type of translator shall be used? 



This involves economics, speed, reUability, types of apparatus 

 available and tractability for making changes. 



