4 Simultaneous Text Messages
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Today in 1890, Thomas Edison received a patent for the Quadruplex Telegraph, his most important telegraph invention.
It transmitted and received four independent signals over a single wire, two in one direction and two in the opposite direction. It allowed Western Union to increase the number of messages the company could send without building new lines and to use its existing lines more efficiently to meet seasonal increases in message traffic.
Western Union ceased its communications operations in 2006 when it became the world’s largest money-transfer business.
