13, for example, is not in use. In response to the number passed by 

 the New York operator, she says "one-three." This notifies the New 

 ^'ork operator that she is going to connect the required telephone num- 

 ber at Philadelphia to circuit No. 13. The New York operator con- 

 nects her calling party to this circuit and conversation begins as soon 

 as the Philadelphia subscriber answers his telephone. As on any local 

 call the removal or hanging up of the receiver at the called telephone is 

 indicated to the New York operator by appropriate signal lights. 



Straightforward Trunking Method 



As improvements in equipment and operating methods were made, 

 the call-circuit trunking method gradually was replaced by the straight- 

 forward trunking method. Let us assume that a call is being handled 

 by the straightforward method from office A to ofifice B. The calling 

 party gives the called number to the operator in ofifice A who then 

 makes connection to a trunk to ofifice B. The trunk is connected to 

 apparatus at office B in such a way that when the operator at A makes 

 connection to it she is connected automatically to the receiver of an 

 operator at B and a momentary audible tone indicates to her that the 

 operator at B is ready to receive the call. Upon hearing the tone the 

 operator at A passes the called number to the operator at B who then 

 connects the trunk to the called telephone line. It will be noted that 

 the selection of the trunk or circuit between the calling and the called 

 offices is made by the originating operator under the straightforward 

 trunking method, whereas under the call-circuit trunking method the 

 selection of the trunk is made by the operator at the terminating office. 



Ringdown Trunking Method 



The ringdown trunking method was the first to come into use and 

 is still used where it is uneconomical to provide the equipment neces- 

 sary to straightforward or dial operation. Under this method the 

 operator at office A signals the operator at office B by making con- 

 nection to a trunk or circuit bet\veen A and B and by depressing a key 

 which operates a signal associated with the circuit at office B. The 

 operator answ^ers this signal by connecting her telephone set to the 

 circuit and announcing the name of her office. The operator at A then 

 passes the number of the called telephone to the operator at B who 

 makes connection to the called number. 



Dial Trunking Method 



Under some conditions it is feasible to arrange for the originating 

 toll operator to dial the called number without the assistance of an 



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