AN IMPROVED TELEPHONE SET 



249 



venience of operation are in fact realized and appreciated by most users, 

 and that accuracy and speed of dialing by the subscriber have not been 

 sacrificed. 



/ input pressure \ 

 ^from artificial mouthj 



/trans- 



Y MITTER 



[tt= 



RECEIVER 



TELE- 

 PHONE 

 SET 



10 DECIBEL 

 TRUNK 



NO. 26 



GAUGE 



LOOP 



48V STEP y 



—I BY STEP WrW 



OR J> 



CROSS- > 



BAR ^ 



M CORD VvHV 



CIRCUIT 



48 V STEP 

 BY STEpH 



OR 

 CROSS- 

 BAR 

 CORD 

 CIRCUIT 



NO. 26 

 GAUGE 

 LOOP 



^OUTPUT PRESSURE^ 

 y^ IN 6CC COUPLER ) 



TRANS- \ 

 MITTER \ 





TELE- 

 PHONE 

 SET 



RECEIVER 



200 400 600 800 1000 1500 2000 2500 3000 4000 



FREQUENCY IN CYCLES PER SECOND 



Fig. 8 — Overall frequency response. 



Ringing 



The new ringer design offers a particularly interesting example of the 

 impact of field experience and knowledge of service requirements on station 

 apparatus design. 



Acoustic surveys of typical subscribers' premises have furnished data on 

 the acoustic transmission losses for ringing sounds, caused by interfering 

 noise, the absorption of walls and hangings, and by doorways, both open 



