TRANSLATORS AND IDENTIFIERS IN SWITCHING SYSTEMS 605 



The improved coding element arrangements in this translator^ have 

 eliminated the output bus-bar multiple entirely (existing in Fig. 6 for 

 instance) as each output code lead terminates in the translator only on the 

 cathode of the reading tube. This improves the safety of the device and 

 helps reduce the cost. But the main benefit is in the improved tractability 

 for changes as they involve only one jumper per input code as compared to 

 three separate jumpers in the previous case. 



Possible Methods of Translator Cost Reduction 



Let us consider again the translators of Figs. 6 and 7, which are modern 

 types for local central offices and used on a sufficiently large scale so that 

 the costs are important, and let us examine where there are possibilities of 

 cost reductions. 



Now these translators are designed for use in buildings with as many as 

 four central office units, that is, 40,000 directory numbers and somewhat 

 less equipment location numbers. Yet each translator can handle only 1000 

 input codes, so if both of these types of translation are involved, 40 trans- 

 lators of one type and somewhat less of the other will be required. Two 

 things may immediately be considered as possibilities for reducing costs: 



(1) Since the two types of translators ejffect translations between the 

 same sets of equipment numbers and directory numbers but in reverse 

 directions, it might appear that savings could be made by providing a 

 single type of translator for both functions and arranged for 2-way operation 

 without requiring duplication of the equipment. 



(2) Since a considerable amount of equipment is involved in the large 

 number of identical selection devices for coding elements in each translator 

 and for connecting devices in the equipment selecting translators, savings 

 might be made by reducing the number of translators required by increasing 

 the speed of operation. 



Electronic Cross-Reference System (2-Way Translator) 



The writer, as a result of considering the foregoing possibiUties a number 

 of years ago, proposed a 2-way translator intended to effect savings over 

 existing schemes of using two different types of translators operating in 

 reverse directions, as in the $5 Crossbar case discussed above. As it was 



^ It is interesting to note that the coding schemes of Fig. 6 and 7 were both proposed 

 by Mr. T. L. Dimond of the Bell Telephone Laboratories. The arrangement of Fig. 7 

 is often referred to as the "Dimond ring" translator. This pun is one of the rare exceptions 

 to dullness in switching nomenclature. 



For an earlier version of the ring type translator see U. S. Patent #2,265,884 issued 

 to Mr. F. A. Korn, of the Bell Telephone Laboratories. Note that this patent applies to 

 an identifier. 



