PUBLIC ADDRESS SYSTEM AND LONG LINES 



153 



V 3 is provided to facilitate adjustment of the by-pass circuit Fi and 

 of amplifier B\ so as to deliver proper volume from Ri both for the 

 local talking and for the reception of the addresses from the distant 

 end of the circuit. The volume indicators F 2 and V 4 at the right- 



Fig. 7 — Two-Way Two-Wire Connection for Addressing Local and Distant 



Audiences. 



hand end of the circuit have functions similar to those of Fi and Vz 

 respectively. 



Fig. 7 is similar to Fig. 6 with the exception that the toll line is of 

 the two-wire type. At each end of the toll line, which may, or may 



Fig. 8 — Arrangement for Connecting Third Point to Circuit of Fig. 7. 



not, contain two-way repeaters, transformers and networks N\ and 

 N 2 are placed for converting the two-wire circuit into a four-wire 

 circuit. The equalized cable circuits at the two ends thus form two 



