inward operator at the called place. By this trunking method the 

 calling party reaches the operator and gives her his call in the usual 

 way. She then makes connection to a trunk or circuit to the called 

 place and upon receipt of the proper automatic signal, indicating that 

 the apparatus at the terminating office is ready to receive the call, she 

 dials the called number. Under this method, as with the call-circuit 

 and straightfonvard trunking methods, switchboard lamp signals 

 indicate to the originating operator whether the receiver at the called 

 telephone is on or off its hook. 



Description of Toll Operating Methods 



General Characteristics of Toll Calls and Operating Methods 



The percentage of toll calls handled by the various toll operating 

 methods has varied from year to year, as shown in Fig. 20, until at 



'^ 55 



_i 



5 50 

 _i 

 O 45 



zi 40 



Fif 



1915 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 1934 



TIME IN YEARS 



. 20 — Distribution of toll calls by operating methods at Bell operated offices in 



the United States. 



present about 99 per cent are handled by the A-Board Toll and 

 Combined Line and Recording methods. A large percentage of toll 

 calls involve short distances and are of a simple type that may readily 

 be handled at local switchboards. The remaining toll calls are handled 



50 



