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BELL SYSTEM TECHNICAL JOURNAL 



steps which have been taken in working out the form of the equip- 

 ment to the degree of efficiency now required for the cable plant. 



In Fig. 1 is shown one of the original forms of repeaters, a number 

 of which were installed as early as 1914. In this case the repeater 

 apparatus was assembled in boxes designed to mount on the wall, each 

 box containing a one-way amplifier. Two such one-way units would 



Wide Rack Through Line Repeater 



be required to form what is now known as a two-way, two element 

 repeater. Although the particular amplifiers shown in the illus- 

 tration were actually used for one-way operation only, they are 

 typical in their general form, of the units employed for two-way 

 operation. The balancing networks, associated coils, etc., were 



