Examples from the Web for quadruplex
I had paid for all the experiments on the quadruplex and exhausted the money, and I was again in straits.
A general knowledge of the principles of quadruplex and multiplex working.The British State Telegraphs|Hugo Richard Meyer
The first quadruplex system was invented by Edison in 1874, and in four years it saved more than half a million dollars.
Quadruplex telegraph, sending four messages over one wire at the same time—Edison, 1873.
For his quadruplex system, Mr. Edison utilized this fact in the construction of a rheostat or resistance box.