MEASUREMENT OF TELEGRAPH TRANSMISSION 



155 



In certain other special tests, where it is desired to obtain a record 

 of the variation in distortion, recording meters have been connected 

 in series with the meters of the set and a continuous record made using 

 either a recurring test message or the signals from the subscriber. 



JHL 



Fig. 7 — Start-stop telegraph transmission measuring seL. 



An idea of the arrangement of the measuring set for central office 

 use may be obtained from the front and rear views which are shown 

 in Fig. 7. It is the practice to provide multiple appearances at 

 telegraph boards in order that one set may be used at any one of a 



