CHARACTERISTICS OF TOLL TELEPHONE CABLES 



301 



In addition to the variations with frequency and temperature there are 

 the initial differences between pairs on account of manufacturing processes, 



150 



14.5 



140 



135 



130 



125 



120 



no 



2 



O 105 



100 



95 



90 



85 



80 



75 



70 



20 



30 



40 



50 



60 



70 



80 



90 



100 



110 120 



TEMP-DEGREES EAHR 



Fig. 5 — Resistance per mile vs. temperature — 19 gauge pairs 



etc. One such source of variation in resistance of pairs is the difference 

 in wire diameters caused by wear of the dies used in drawing wire.* The 



« John R. Shea and Samuel McMuUan, "Developments in the Manufacture of Copper 

 Wire," B.S.TJ., VI (April 1927)^pp. 187-216, 



