AN IMPROVED THREE-CHANNEL CARRIER TELEPHONE SYSTEM 73 



the same manner. Wire sizes of 104 mil, 128 mil and 165 mil are 

 commonly used in the Bell System plant, the particular size often 

 being governed by mechanical rather than by transmission considera- 



.20 



.10 



.05 



2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 

 FREQUENCY - KILOCYCLES 



Fig. 18 — Attenuation characteristics of 104, 128 and 165 mil open-wire lines. 



tions. These lines are carried into the terminal and repeater offices 

 through cables which are usually loaded to maintain smooth impedance 

 relations and reduce the transmission losses. 



The control of crosstalk ^ is one of the major problems in the 

 application of carrier to open-wire lines. On short lines where only a 



