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BELL SYSTEM TECHNICAL JOURNAL 



Panel Dial System 



In the largest cities and the smaller municipalities around them 

 making up the large metropolitan centers, a much greater degree of 

 complexity is encountered in switching the calls due to the large 

 number of offices of varying types to which calls are destined and due 



Fig. 18— Typical panel selector frame. Capacity 30 selectors in front and 30 

 selectors in rear. Motor driving mechanism is at the bottom of frame and controllinc 

 apparatus at either side. 



