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BELL SYSTEM TECHNICAL JOURNAL 



not required at each repeater station and the general matter of balance 

 and consequently good repeater operation in the circuit as a whole is 

 greatly simplified. This arrangement can, therefore, be satisfactorily 

 used for long circuits where two-wire operation might be impracticable, 



Fig. 24 — Group of Repeaters at Reading, Pa. 



and examples would be such circuits as New York-Pittsburgh or New 

 York-Chicago. 



Both of these types of circuits may be operated on No. 19 A. W. G. 

 four-wire facilities which may be either physical or phantom circuits. 



Fig. 24 shows a group of repeaters installed in the office at Reading, 

 Pa., and Fig. 25 shows one of the four-wire repeater units in somewhat 

 greater detail. 



