This line of switchboards is illustrated in Figs. 303 to 306.
In 1896 there came a most revolutionary change in switchboards.
Since then, there have come some switchboards that are wholly automatic.
B boards are switchboards in which terminate the incoming ends of the trunk lines leading from other offices in the same exchange.
The hinge of the key shelf is an important feature and is universally found in all switchboards of this general type.
I glanced toward where a black portal broke the circle of switchboards, and shuddered.
To my right were the big generators and the switchboards, gleaming with copper bus-bar, and intricate with their tortuous wiring.
It would compel the rebuild-ing of the switchboards and the invention of new signal systems.
And here, too, were many of the ablest inventors and engineers, who did most to develop the cables and switchboards of to-day.
Some action had to be taken quickly, so licenses were given to four other manufacturers to make bells, switchboards, and so forth.