American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 297
the purpose one side of each of the above mentioned quadcircuits, and it was necessary that each of those offices should be able to communicatewith each other, exactly as though all the offices were on a single wire. An arrangement devised by the writer to meet those requirements is to be seen… … The first sides of the quads are supposed to be used in this instance, consequentlythe pole-changers pc^, pc^, pc^, and polar relays pr^, pe,^ pr3^ ^^f ^]^q respective sets,only, are shown. In each case the polar relay controls a repeating transmitter rtS rt,^KT^. In the figure, the polar relays…
Telegraph
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