PUBLIC ADDRESS SYSTEM AND LONG LINES 



151 



merit of amplifier L\ to be made so that the power delivered to the toll 

 line will be within the proper limits. As explained above if the volume 

 at the toll office is allowed to become too great, the telephone repeaters 

 on the toll line will be over-loaded and serious distortion will result, 

 while if the volume is allowed to become too weak, extraneous noise 



Toll Line with One Way Repealei 



-----13 



D, D 2 etc D n 



Fig. 4 — One-Way Connection to Point in Distant City. 



and crosstalk will tend to obliterate the direct transmission. If a 

 distant talking transmitter is used for the speaker, a multi-stage ad- 

 justable amplifier is associated with it. In this case the volume 

 indicator is located at the output of this amplifier as shown by the 

 dotted lines in Fig. 4. When the volume indicator is employed at 

 this point it is necessary to take into account the loss introduced by 

 the non-loaded cable and the equalizer E it together with the gain of 

 the repeater d, in order to deliver volume within proper limits to the 

 toll line. The toll line, shown equipped with repeaters D\, D 2 , etc., 



Non Loaded 

 Cable 







Toll_Office_ _ 



C, 



Toll Line to 

 Distant Point X 



c 2 



Fit 



Toll Line to 

 Distant Point Y 



5 — One-Way Connection for Addressing Local and Distant Audiences 

 Simultaneously. 



extends to the toll office in the distant city. At this point the am- 

 plifier Ci is located, together with another equalizer E%, for correct- 

 ing the distortion in the local non-loaded cable circuit. The apparatus 

 at the point where the audience is located is similar to that shown in 

 Fig. 3. 



