TRANSMISSION FEATURES OF NEW TELEPHONE SETS 371 



the susceptiveness of the set to interfering noise by as much as 15 db. 

 A further material reduction is realized by the high impedance of the 

 ringer used in the new sets, so that in most cases interfering noise at 

 grounded ringer stations will not differ materially from that at indi- 

 vidual stations where the ringer is bridged across the line. 



STATION IN USE 



STATION NOT IN USE 



I I CORD 



I LOOP CIRCUIT 



B - POSSIBLE SINGLE-CONDENSER ARRANGEMENT 



Fig. 6 — Ringing arrangements for party line service. 



It is interesting to note that this improvement is realized at little 

 additional cost, since the transmission condenser, which must be of 

 relatively high capacitance, is permanently bridged by the transmitter, 

 so that it is protected from exposure to any large voltages, and may 

 be of cheaper construction and smaller in size than would otherwise 

 be the case. The ringing condenser on the other hand, while it must 

 be constructed to withstand higher voltages, may be of relatively 

 small capacitance, which gives more uniform and better ringing and 

 dialing performance. 



Characteristics of Transmitter and Receiver 

 Since the individual design characteristics of the new transmitter 

 and receiver are discussed elsewhere,^ attention here will be centered 

 on the overall effects of these characteristics in the complete trans- 



