a website collaboration between Science Service and the Smithsonian Institution

1938 - elaborate sending apparatus at the Philadelphia terminal


CD 2055046 E&MP5.013

Cables, Coaxial


Feeding 240 standard signal bands, coming into the exchange over 240 pairs of wires, into a single cable, requires almost as much equipment as a small broadcasting station.

At the other end of the line, a similar setup separates the signals, sending them out over separate pairs of wires.

Terminal equipment today limits the number of signals that can be sent over the coaxial cable.

The coaxial cable is limited in carrying power only by the nature of the terminal equipment. Here is shown the elaborate apparatus at the Philadelphia terminal.

The Philadelphia terminal of the coaxial cable, showing a Laboratories’ engineer at the panel, where jacks are provided for each incoming and outgoing telephone channel. 

Original Caption by Science Service
©Bell Telephone

National Museum of American History


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