82 Telephone Systems of the Continent of Europe 



spoken through. When two trunks are connected the phonic call 

 and the indicator of one of them are cut out, leaving the remain- 

 ing indicator to act as ring-off, 



At Mons and Namur a more simple arrangement, devised by 

 M. Delville, is in use, the plan of which is shown in fig. 19. The 

 wires of the trunk wi W2 come to the Dewar key D and the jacks 

 ji J2. The spring of ji is connected to the contact a of jack J3, 



C2 



FIG. 19 



while that of J2 is joined to one end of the translator secondary 

 TI. The other end of the secondary goes to the contact b of J3, 

 which is normally insulated from a. The frame of 73 is connected 

 to earth through the primary TP of the translator. When D is up, 

 the phonic call PI P2 is in circuit with the line ; when depressed, 

 the operator's phone and the secondary of its transmitter induction 

 coirare cut in. The primary circuit of this coil is closed through 



