Applications for the Quadruplex Telegraph

Even after the invention of the telegraph, most personal communication still had to travel by mail. This was extremely slow, but telegraph technology was new, expensive, and not extremely widespread. It took the breakthrough of the quadruplex telegraph to make this sort of communication viable.

“Most of the continental state telegraphs at this time had a zone (distance) tariff for a standard message (either fifteen or twenty-five words, with five word increments), charging as well for addresses and for delivery outside of the destination town. A one hundred word limit was commonly imposed on public messages.”

- Steven Roberts (Historian)

Before the quadruplex telegraph, sending messages was more expensive and uses were limited. Many messages were from governments or large companies that could afford it.

The quadruplex telegraph could send four times as many messages with the same infrastructure cost, so the cost of each message significantly decreased. Each message cost about a quarter as much to send, although in practice, the gain was closer to one third to one half of the original price. Around the time of the invention, prices dropped from about one dollar to thirty cents per telegram.

Thomas Edison, 1922, Library of Congress

These lowering costs allowed increased telegraph use in a wider variety of applications. Initially, the telegraph was mostly used by large railroad companies for scheduling. As the quadruplex improved telegraph technology, business and stock market information could be sent in much larger quantities. It also opened up the possibility of affordable personal communication.

Data from "History of the US Telegraph Industry"

The quadruplex telegraph was invented in 1874, and the cost of sending telegrams dramatically drops around this time. Additionally, this lower cost allowed many more telegrams to be sent.

The quadruplex telegraph was the first step in making fast, reliable communication affordable for individuals.