THE COMPANDOR 



317 



of the individual talker are taken into account, it is even greater than 

 40 db. 



Volume Range of a Telephone Circuit 



There are two limits on the range of volumes which a system can 

 transmit. The upper limit of volume is set by the point at which 



-25 -20 -15 -10 -5 



DECIBELS RELATIVE TO MAXIMUM VOLUME 



Fig. 1 — Volumes of 950 local subscribers at New York transatlantic switchboard, 



January-April, 193 L 



overloading appreciably impairs the signal quality or endangers the 

 life of the equipment. It is an economic limit set by the cost of build- 

 ing equipment of greater load capacity. The lower limit of volume is 

 set by the combination of the amount of attenuation and the amount 

 of interference in the system such that the signal should not be appre- 



