DEVELOPMENT IN TELEPHONE SERVICE 



2 33 



that in the pressure of cleaning batteries, or sweeping the room or 

 doing some other kind of work, boy-like he forgot to disconnect the 

 circuits. 



With Mr. Coy's first board two telephonic connections only were 

 possible at the same time. That is, two conversations only could be 

 carried on at the same time. If a third subscriber desired connection, 

 it was necessary to await the release of a lever by the disconnection of 

 one of the other lines. Then the bright thought occurred to the boy- 

 operator that by wetting the tips of his fingers and placing them on the 

 respective pegs, his arms would become the levers of the respective 

 circles, and thus the two subscribers could talk through his body. 

 This very ingenious makeshift served to tide over the brief period 

 during which an addition of two more circles was made to the original 

 board, thus increasing its capacity fifty per cent. But one day, while 

 the boy-operator was letting his wet finger-tips perform the service, 

 now taken care of by cords and plugs, the ring-off signal came in 

 from a subscriber who had just had a powerful magneto installed, and 

 the shock received ended that very convenient practice. 



Soon there were more than 

 150 subscribers on twelve sub- 

 scriber-lines, and the ratio of 

 calls per subscriber was constant- 

 ly on the increase. So a new 

 board was planned by Mr. Coy 

 — and built by Mr. Snell, who is 

 still in New Haven engaged in 

 supplying equipment-specialties 

 to telephone companies. This 

 board (Fig. 10) had a line ca- 

 pacity of forty wires. Evidently 

 switchboards of this type found 

 favor for a time in the opinion 

 of the parent company; for a 

 circular issued in 1880, by the 

 National Bell Telephone Com- 

 pany, contains the following sug- 

 gestions, all of which were omitted from a circular of similar purport, 

 issued a year later by the American Bell Telephone Company : 



There are several styles of switchboards that may be used, all depending 

 on the general principles for tneir operation. They consist essentially of 

 horizontal and vertical bars crossing one another and arranged so that any 

 horizontal bar can be connected to any vertical bar. It is chiefly in the 

 methods of making the connection that the various switches differ. In what 

 is known as the ' plug ' switch, the connection is made by inserting a small 

 metal plug at the point where the horizontal and vertical bars cross one an- 

 other. There are several forms of the plug switch. ... In what is known as 

 the slide central office switch, the connections are made by means of a sliding 



Fig. 11. 



