374 BELL SYSTEM TECHNICAL JOURNAL 



removed. Indeed, simplex operation may in this case possess a 

 real advantage over duplex from the commercial point of view since 

 it permits dividing the carrying capacity of the cable most efficiently 

 to handle the excess of traffic in one direction. 



Although means have been made available for making efficient 

 use of the loaded cable it should be recognized that the method of 

 operation best suited to satisfy commercial demands must be deter- 

 mined from future experience with cables of the new type. This is 

 especially true with regard to relatively short cables. The discussion 

 of the loaded cable problem in this paper has been confined wholly to 

 the realm of long ocean cables where the limitations of the cable 

 rather than terminal equipment or operating rec|uirements determine 

 the best design. This is the simplest case and the one which at present 

 seems to show the greatest gain from loading. Where traffic require- 

 ments are limited and where there is no prospect of ever requiring 

 higher speed than can be obtained with a non-loaded cable of reason- 

 able weight, the ad\'antage of loading is less and becomes smaller 

 as the weight of non-loaded cable which will accomplish the desired 

 result decreases. It should not be concluded, howe\er, that loading 

 will not find important application to short cables. Many short 

 cables are parts of great systems and must be worked in conjunction 

 with long cables. In such cases it may pay to load short sections 

 where otherwise loading would not be justified. Permalloy loading 

 also offers great possibilities for multiple-channel carrier-telegraph 

 operation on both long and short cables and with this t>pe of opera- 

 tion in prospect it is too early, now, to suggest limits to the future 

 applications of permalloy to cables or to predict what will be its 

 ultimate effect on transoceanic commimication. 



