348 Telephone Systems of the Continent of Europe 



tion is effected by replacing the plugs or depressing the finger 

 stud. The general arrangement of the jacks, test and restoring 

 circuits is shown in fig. 117, which explains itself. The attention 

 signal, included in the night-bell circuit, is intended to assist the 

 lady superintendent. Each operating section has two one with 

 a white flag in connection with all the signalling indicators of that 

 section, the other with a red flag in connection with all the 

 ring-off drops of that section. Small white and red glow lamps 



FIG. 116 



have been tried instead of indicators with coloured shutters ; they 

 answer perfectly, and as self-restorers cannot be surpassed. By 

 their position the superintendent can see whether any signalling 

 drop has fallen and remains unanswered, or any ring-off has been 

 given and left unnoticed. To enable operators to detect a dis- 

 connection on a subscriber's line, a polarised electro-magnet 

 working a visual signal is included in the ringing circuit, the 

 armature of which oscillates during ringing if the line is right. 



