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BELL SYSTEM TECHNICAL JOURNAL 



man in one part of the country may communicate by word of 

 mouth with another in a distant part. 



"Believing, as I do, that such a scheme will be the ultimate 

 result of the telephone to the public, I will impress upon you all 

 the advisability of keeping this end in view, that all present 

 arrangements of the telephone may be eventually realized in this 

 grand system." 



Early Developments 



The only apparatus available at that time for this purpose was 

 that employed in telegraph, messenger, fire and burglar alarm services. 

 Some of this apparatus, such as wire, insulators, batteries, annuncia- 

 tors, etc., was found to be useful in the new art; other apparatus had 



Fig. 1 — Early Type Switchboard 



to be developed. The switchboards of that clay employed this ap- 

 paratus. They were small in size, and could accommodate only a 

 limited number of lines. 



It soon became evident that the requirements of the telephone 

 exchange service demanded signaling and switching equipment 

 different from that employed in any of the other branches of the 

 electrical industry, and it became necessary to create an entirely 

 new art, invoking many branches of science, before commercial 

 telephone service could be given on an adequate scale. The switch- 

 boards grew from small boards, capable of handling a few lines, as 



