CONQUEST OF DISTANCE BY WIRE TELEPHONY 3Q7 



CONCLUSION 



The end of the present story is at hand. 



It has shown the principal high spots of a most fruitful period in the 

 development of long distance telephony, either \vhen the specific accom- 

 plishments are taken into account in their own right or when they are 

 considered as foundations for the subsequent developments which first 

 made universal telephone service on the North American continent eco- 

 nomically practicable, and then b)' radio links the inclusion of this network 

 within a world-wide international network. 



The prediction in the Carty memorandum of 1909 that a successful tele- 

 phone repeater would also unravel the problems of radio telephony was 

 amph' fulfilled six years later. 



The advent of the high vacuum tube repeater closed the era under review 

 and has of course proved to be an outstanding legacy for the succeeding 

 years. The initial aim during its commercial development was to overcome 

 distance, then to improve the transmission standards. In time, these 

 efforts made excellent transmission performance substantially independent 

 of distance. ^^ 



As these objectives were approached and realized, the general develop- 

 ment emphasis turned in various ways towards the reduction of the costs of 

 the long distance facilities and the provision of much larger circuit groups; 

 b\' the application of carrier telephone systems to open-wire lines, incident- 

 ally requiring the removal of the remaining voice-frequency loading; by the 

 extensive use of repeatered, loaded, cables along routes where large groups 

 of circuits were required, and where stability of service had become very 

 important; and in recent years, by the application of wide-band carrier 

 telephone systems to open-wire and to non-loaded cable, and to coaxial 

 conductor systems. In these developments, the repeater played its own 

 basic part in offsetting attenuation; and other new developments, in par- 

 ticular the electric wave filters, distortion corrective networks, and regulating 

 devices played their parts in shaping and controlling the transmission 

 medium. These various developments were basic to the improved speed 

 of service and the reduced rates, which, along with the high quality trans- 

 mission standards, have stimulated an ever increasing demand for long 

 distance telephone service. 



Some important aspects of these developments which followed the first 

 transcontinental line, and other associated developments, are described in 

 Jewett's article, ''Transcontinental Panorama," published in the January 



'1 The following pertinent quotation is from the 1922 company report to the 

 stockholders: "In faithful reproduction of speech at a distance so that the person listening 

 will understand with ease, so that the speech transmitted will be of proper volume and 

 quaUty without distortion, our engineers and scientists have achieved what seemed to 

 be the" impossible. On the through lines, distance has been eliminated." 



