NEW YORK-CHICAGO CABLE 



85 



ings to furnish current of the proper characteristics for operating the 

 apparatus, and storage batteries are provided to insure uninter- 

 rupted service. As an indication of the size of these plants the 24- 

 Nolt storage batteries installed for the initial load at Bedford have 

 a capacity of 2240 ampere-hours and this provides about one day's 

 reserve. The capacity can, of course, be increased as repeaters are 

 added from time to time when additional circuits are needed. Storage 

 batteries of smaller sizes supplying current at potentials of 30, 120 

 and 130 volts are also provided. 



Examples of Circuit Arrangements 



Fig. 30 shows two possible methods of building up a Philadelphia- 

 Pittsburgh terminal circuit and Fig. 31, a method of building up a 

 New York-Pittsburgh terminal circuit. In all three cases these 

 telephone circuits are intended to have a transmission equivalent of 

 about 12 miles of standard cable. Some Philadelphia-Pittsburgh 



Fig. 29 — Test and Repeater Station at Ligonier, Pa. 



terminal circuits of the first type have been in everyday operation 

 for several months, but it is not the most economical arrangement 

 that it is possible to obtain for general use in providing this or similar 

 service. It will be noted that No. 19 four-wire facilities are used 

 between Philadelphia and Harrisburg and four-wire repeaters are 

 located at these two points. At Harrisburg the four-wire circuit is 



