684 



THE BELL SYSTEM TECHNICAL JOURNAL, JULY 1952 



The branching network at the outlying terminal has low impedance. 

 Taps on the transformers in the network permit the impedance ratios 

 to be adjusted to suit the line impedances between which the network 

 operates. Since several circuits may pass through this network, a short- 

 circuit on one branch should not be capable of degrading transmission 

 in the other branches. To prevent this, resistances are inserted in series 

 with each branch of such a value that a short circuit will not cause more 

 than 3 db excess loss in other channels. It has been sho\m by tests that, 



TYPE C 

 REPEATER 



OR 

 TERMINAL 



121 A 

 FILTER 



VOICE 



FREQUENCY 



REPEATER OR 



TERMINAL 



43A1 

 CHANNEL 

 TERMINALS 



150A 

 FILTER 



-1 



HP J 



' T SET 



LP -■ ' 1 



SUBSCRIBER SETS 



Fig. 12 — System layout, above the voice. 



BRANCHING 

 NETWORK 



130B1 



SUBSCRIBER 



SETS 



TELEPHONE 

 REPEATER 





^-r-\ 



Fig. 13 — System laj-out, in voice band. 



e- t 



BRANCH 

 LINES 



