progress. The conditions bearing on the telephone toll j^lant and toll 

 service are constantly changing through growth, shifting demands, the 

 development of new needs of customers for telephone service. Also, 

 the best means and methods available for giving service are constantly 

 developing as a result of the experience of the various operating 

 companies and through the development of new instrumentalities and 

 operating methods by the headcjuarters forces of the Bell S>'stem. 

 These types of apparatus and of communication systems, and methods 

 and practices for construction, maintenance or operation represent the 

 outcome of careful consideration of the best way to meet a t>pe of 

 situation. Through the headquarters organization their availability 

 is made known at once to the operating telephone companies of the 

 Bell System throughout the country with information regarding their 

 desirable fi^d of use. This greatly facilitates their adoption and 

 application by these Companies. 



In some cases, such new standards present means for doing something 

 which could not be done before. In many cases, such new standards 

 replace existing standards due to advances in the art, improvements 

 in methods or technique, or changes in operating requirements. 

 Standardization in the Bell System, therefore, involves a continuous 

 procession of new standards to meet new conditions or to meet old 

 conditions better than was heretofore possible, and the subsequent 

 dropping of old standards. Such standardization is based not only 

 upon the present needs of the telephone system, but also upon the 

 best picture which can be formed of future trends. It is essential to 

 the rapid and satisfactory development of telephone toll service. 



Bibliography 



Page 

 Number of 

 Statement Title A iithor 



Early Developments: 



2-15 "Beginnings of Telephony" F.L.Rhodes 



N. v., Harper and Brothers, 1929, 261 pp. 

 2-15 "Some Recent Advances in Telephony" Thomas D. Lockwood 



A. I. E. E. Transactions, Vol. Ill, 1886, p. 74- 

 93. 

 2-3 "Speech and Hearing" Harv^ey Fletcher 



N. Y., D. Van Nostrand Co., Inc., 1929, 331 pp. 



2 "The Development of the Microphone" 1 1. A Frederick 



Bell Telephone Quarterly, Vol. 10, Jul\- 1931, 

 pp. 164-188. 



3 "The Carbon Microphone" F. S. C.oucher 



Journal of the Franklin Institute, Vol. 217, April 



1934, pp. 407^42; 

 Bell System Technical Journal, Yo\. 13, April 



1934, pp. 163 194. 



72 



