586 



BELL SYSTEM TECHNICAL JOURNAL 





15 20 25 30 35 40 45 50 



FREQUENCY IN KILOCYCLES PER SECOND 



55 



Fig. 20 — Typical overall transmission frequency characteristic of high frequency line 

 between New York and Charlotte, N. C. (B), and New York-Washington (A). 



come objectionable on future long systems and it is planned to improve 

 this characteristic by means of different equalizers. 



The overall transmission frequency characteristic of a channel on a 

 New York-Charlotte type K system is shown by Fig. 21. Measure- 



0.2 0.4 0.6 0.6 



1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 

 FREQUENCY IN KILOCYCLES PER SECOND 



2.8 3.0 3.2 3.4 3.6 



Fig. 21 — Overall transmission frequency characteristic of a type K carrier channel 

 between New York and Charlotte, N. C, as measured between two-wire voice 

 frequency lines. 



ments for this characteristic were made between the two-wire sides of 

 hybrid coils connected to the two directions of carrier transmission of 

 the channel concerned. 



Use of Initial Systems 



Telephone message circuits are being operated over most of the type 

 K channels now available for use. In most cases the channels are 

 used as parts of circuits which are longer than the carrier systems. For 

 example, most of the 60 channels between New York and Charlotte, 

 N. C, are used for circuits between New York and southern cities 

 beyond Charlotte. Some of these circuits are obtained by connecting 

 type K carrier channels at Charlotte to channels of type J open wire 

 carrier systems which operate between Charlotte and West Palm Beach, 

 Fla. Of the 204 channels available for use, only 21 are used as all 



