quadruplex telegraph, sending four messages over one wire at the same time—Edison, 1873.
The first quadruplex system was invented by Edison in 1874, and in four years it saved more than half a million dollars.
The next step was a quadruplex system, by means of which four messages may be transmitted over one wire at the same time.
Gould paid for the quadruplex system thirty thousand dollars, but for the automatic telegraph he paid nothing.
A general knowledge of the principles of quadruplex and multiplex working.
For his quadruplex system, Mr. Edison utilized this fact in the construction of a rheostat or resistance box.
The quadruplex has not as a rule the same working efficiency that four separate wires have.
I had paid for all the experiments on the quadruplex and exhausted the money, and I was again in straits.
At this juncture other schemes were fermenting in his brain; but the quadruplex engrossed him.