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THE BELL SYSTEM TECHNICAL JOURNAL, APRIL 1951 



exchange area cables are given in Table IX. The tabulation, in general, is 

 in the sequence of ascending costs. Although loaded 24 ga. cable is superior 

 to non-loaded 22 ga. cable from the transmission standpoint, it was not 

 sufficiently cheaper (when using iron-dust core loading coils) to warrant 

 its general use. However, under some special circumstances involving large 

 complements of the new coils, loaded 24 ga. cable could be proved in. 



In the design of the cable plant, the signaling characteristics of the facili- 

 ties of course had to be taken into account along with the transmission 

 characteristics. In some situations the total costs could be reduced by using 



Table IX 

 Transmission Characteristics of Typical Exchange Area Trunks 



a more expensive grade of circuit that allows the use of less expensive sig- 

 naling equipment. 



(18) Loading Coils for Higher Cut-Off Loading Systems 



18.1 New Small-Size Coils for M88 Loading 



Preliminary design studies of cheaper and smaller loading coils for use on 

 22 ga. cables started well in advance of the decision to standardize M88 

 loading. It was realized that the maximum possible economies would result 

 from a two-stage development plan, in which the first stage would consist 

 of an improvised "stop-gap" design using available standard core-rings and 

 simple modifications of existing standard loading coil cases, and the second 

 step would be an entirely new design, having approximately optimum pro- 



