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BELL SYSTEM TECHNICAL JOURNAL 



Having secured the desired telephone number from the directory, 

 which we will assume is "ACAdemy 1234," the subscriber will first 

 remove his receiver from the hook and will hear the so-called "dial 

 tone," which indicates that the apparatus is ready to receive the call. 

 He will then insert his finger in the hole over the letter A, rotate the 

 dial until the finger comes in contact with the metal stop shown in 

 the picture, then release the dial, which will automatically return to 

 normal. He will repeat this operation tor the letters C and A, and 

 in turn tor the four numerals, /, 2, J, 4. 



This operation of dialing on the part ot the subscriber is exactly 

 the same, whether the telephone number he desires is in a manual 

 or a machine switching office. Similarly, the method employed by 

 a subscriber who is connected to a manual office in getting a sub- 

 scriber connected to a machine switching office, is the same as though 

 the desired subscriber were connected to another manual office. 



Fig. 8 — Diagram Showing Connections from Machine Switching to Machine Switch- 

 ing, Machine Switching to Manual and Manual to Manual Switching 



The progress of a call originating in a machine switching office is 

 briefly as follows: 



As will be seen from Fig. 8, the line of the calling subscriber, whom 

 we will assume to be a subscriber in the Academy office, appears in a 

 so-called "line finder" frame. When the subscriber's receiver is 



