High-Speed Ocean Cable Telegraphy 



By OLIVER E. BUCKLEY 



Synopsis: The invention of permalloy and its application to submarine 

 cables have led to the installation of transoceanic cables of many times the 

 traffic-carrying capacity of the former non-loaded cables. This paper relates 

 briefly the history of the development of permalloy-loaded cables and dis- 

 cusses certain outstanding problems concerned with their design, construc- 

 tion and operation. In a concluding general survey the field of usefulness 

 of loaded submarine telegraph cables is considered. 



To a considerable extent the paper is a critical summary of material 

 previously published by members of the staff of the Bell Telephone Labora- 

 tories. Its scope is indicated by the sub-titles as follows: 



Loaded Cables Now in Service 



Historical Remarks 



Permalloy and Its Application to Cables 



Principles of Design of Loaded Cables 



Principles Involved in Operation 



Apparatus for Restoration of Signals 



Apparatus for Automatic Operation 



Electrical Measurements of Loaded Cables 



A General Survey 



VOLTA devised his famous pile in 1799. Less than 60 years 

 later, in 1858, the first telegraph message was sent over an 

 Atlantic cable. Now nearly 70 years have passed since the remarkable 

 feat of transatlantic telegraphy was first accomplished. Although 

 the art of cable telegraphy may therefore be considered old, it cannot 

 be said ever to have stopped growing. At all periods of its growth 

 it has offered an interesting field for technical endeavor. An added 

 interest was attached to it a little more than 25 years ago when Mar- 

 coni, by his famous demonstration of transatlantic radio telegraphy, 

 introduced a competitor. With the birth of this new child of science 

 arose the question as to whether the art of telegraphing over cables 

 would not ultimately die. But radio too required time to grow, and 

 it is only within very recent years that there has been occasion for 

 serious concern as to the future of the older art. Now a new advance 

 has been made on the side of the cables and the race for supremacy in 

 transoceanic communication has taken a new turn. The advance to 

 which I refer is the introduction of the high-speed permalloy-loaded 

 cable, and it is with regard to this advance that I wish to speak. 



My object is to tell briefly what has been accomplished with cables 

 of the permalloy-loaded type and to describe some of the outstanding 

 features of development which have led to this accomplishment. No 

 attempt will be made in what follows to discuss all phases of cable 

 design and construction, but my remarks will be confined principally 

 to those aspects of cable telegraphy with which the work in the Bell 

 Telephone Laboratories has been concerned. 



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