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BELL SYSTEM TECHNICAL JOURNAL 



battery supplies the plate voltage for the tubes. Each amplifier re- 

 quires about 22 volts for the tube heaters and this is obtained by 

 dividing the battery into seven sections, each section supplying several 

 amplifiers in parallel. Additional power supplies of 55-volt alternating 



Fig. 17 — Interior of auxiliary repeater station. 



current and 140-volt direct current are required for the regulator 

 system. 



In the station, there are alarm circuits, which signal the nearest 

 attended office if trouble develops. There are alarms for blown fuses, 

 high or low battery voltages, power failures, etc. A telephone order 

 wire to the nearest attended station is provided for the maintenance 

 force. 



