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DELL SYSTEM TECHNICAL JOURNAL 



coin has been deposited, the sender allows the called subscriber to be 

 rung and permits the conversation. In case the called subscriber 

 is busy or does not answer, or if the call is to a free line, the sender 

 returns the coin to the calling party. If the called party answers, 

 the sender causes the coin to be collected. 



The sender makes a test of the calling line after the subscriber has 

 completed dialing, to insure the deposit of the coin, and recognizes 

 whether a coin has actually been deposited or whether some abnormal 

 condition exists, in which case the call will be routed to an operator 

 who causes an investigation to be made. 



7. In large areas, such as the New York Metropolitan area, there 

 are distant points, connection to which requires toll charges. In 

 such cases the subscriber is instructed to dial a special operator who 

 will ascertain his wishes, complete the call, and make the prope: 

 charge. Should a subscriber attempt to dial outside of his own local 

 service area, his call will automatically be routed to an operator. 



Fig. 9 — Views of the Selector 



Panel Type Selecting Mechanism. An important mechanism of a 

 machine switching system is the selector and its associated multiple 

 bank. It is a device by means of which trunks or lines are connected 

 together as required. It performs the same function as the switch- 

 board cord and plug which in a manual exchange can be plugged by 

 the operator into any one of a number of jacks which are the terminals 

 of trunks or lines. 



Fig. 9. shows the mechanical elements of the selectors. The mov- 

 able member corresponds to the cord and plug of the manual system 



