so.ui: rr.h'y i.oxc, rEi.r.riioxF. circuits 



497 



tion with weather ctxKlitions arc also ronsiclcrably reduced. Further- 

 more, the use of this t\pe of circuit fits in with tiie ap|)lication of 

 carrier current systems for which it is ad\antageoiis to use nou-' 

 K)ade<l Itiii mil circuits where these arr a\ailal)le.''' 



With the improxi'd repe.iters and halancinj; networks it is possible 

 Id oi)tain a higher decree of balance at the various re[)eater points. 

 The improved transmission characteristics of these repeaters also 

 contribute toward better c|ua!ity. Both of these improvements arc 

 important in view of the increased number of repeaters in the circuit. 



The use of this improved t\'pe circuit has been extended during the 

 last few years to connect a large number of the important cities in 

 the I'nited States. A few of the longer circuits are: 



One of the most recently established of these circuits is the Chicago- 

 Los Angeles circuit routed over the southern transcontinental line. 

 This and other through circuits on this line from Denver via El Paso 

 to Los Angeles were established last year in order to provide for the 

 growth in transcontinental traflfic and to make available a second 

 route as protection for the through ser\ice to the Pacific Coast. A 

 brief description of these circuits will be given as typical of the long 

 open wire circuits on this and other routes. 



In the following, certain data based on actual experience with 

 circuits on the southern transcontinental route, and in certain in- 

 stances on circuits on the central transcontinental route are given. 

 These data, however, are in general representati\e of results ob- 

 tained on circuits of the same type throughout the Bell -System. 



From Denver west, a phantom group of four 165 mil wires pro- 

 vides for a Chicago-Los Angeles circuit, a Denver-FI Paso circuit, 



'Refer to paper entitled "Practical .\pplication of Carrier Telephone and Tele- 

 graph in the Bell System," by .■\rthur F. Rose, Technical Journal, .-Xpril, 1923. 



