work is indicated in Fig. 16. It will be noted that this network con- 

 nects together almost all of the major places between the Atlantic 

 Seaboard on the East; Atlanta, Georgia and Dallas, Texas on the 

 South; Western Texas, Kansas City, and Omaha on the West; and 

 Toronto, Montreal, and Bangor on the North. In addition, there are 

 other sections of toll cable connecting important centers as San 

 Francisco-Los Angeles and Miami-Palm Beach. These cable systems 

 provide a storm-proof outlet for telephone circuits to 155 out of a total 

 of 210 cities over 50,000 population in the United States and Canada, 

 and cover the major part of the United States in which open-wire lines 

 are subject to interruption by severe sleet storms. The cable network 

 includes at the present time about 27,000 miles of cable and 12,500,000 

 miles of conductor. 



-2.6 INCHES (aPPROx) 



FOUR-WIRE NO. 19 GAUGE QUAD 

 IFOR TRANSMISSION IN ONE 

 DIRECTION 



FOUR-WIRE NO. 19 GAUGE QUAD 

 I FOR TRANSMISSION IN OPPOSITE 

 DIRECTION 



@ NO. 16 GAUGE PROGRAM PAIR 



I TWO-WIRE NC 

 GAUGE QUAD 



r~\ TWO-WIRE NO. 16 OR NO- 19 



MAKE-UP 



19 QUADS NO. 16 AW GAUGE 



6 PAIRS NO. 16 AW GAUGE 



114 QUADS NO. 19 AW GAUGE 



Fig. 15 — Cross-section of typical toll cable. 



The Time Factor In Telephone Transmission 



In the above discussion of toll cable systems it was mentioned that 

 it became desirable for the long circuits in cable to provide a type of 

 circuit having a higher velocity of transmission than that of the loaded 

 cable circuits previously in use. The effects of the length of time 

 required for transmission over long circuits, while particularly notice- 

 able in long cable circuits, are of importance in long open-wire circuits 

 as well. These effects are briefly discussed below. 



On non-loaded lines, either in open wire or in cable, the velocity 

 of transmission of telephone currents over the line conductors is high, 



26 



