Communication Technologies Impacted by the Quadruplex Telegraph

The quadruplex telegraph was more than just a set of cool tricks to improve telegraph communications. It was an early form of signal multiplexing, compression, and encoding that led to many derivative technologies. Multiplexing refers to technologies that combine several signals into one stream of data, and then decode them at the other end.

One of these derivative technologies is known as Charlieplexing. It relies on similar tricks using polarity to enable a small number of wires to control many devices. It is often used in light based display panels and keypads. Multiplexing techniques are also used in some forms of radio and television broadcasting.

“Multiplexing was designed to send numerous analog signals or digital streams through one common transmission line.”

- Donald Krambeck (Electrical Engineer)

This can also be seen in modern internet communications. Packets of data are sent between different computers and servers. All of these packets must travel on relatively few wires, and must each arrive and be decoded accurately. The modern bandwidth of the internet would never have been possible without these early advancements in sending and receiving more data with less infrastructure.

Multiplexing Techniques, 2006, Socratic Electronics

This animation shows a simplified version of some modern multiplexing techniques. Multiple messages are sent down one wire by rapidly switching the current message that the wire is carrying.

Our modern economy relies on the rapid exchange of massive amounts of data. Our personal lives are greatly improved by easy access to information. Modern social movements rely on the ability of individuals to easily communicate in order to affect change. This transfer of data is only possible with multiplexing, which was first commercially implemented in the quadruplex telegraph.

The quadruplex telegraph was clearly much more than just a better way to send telegrams. It was a communication breakthrough that had an enormous impact on the modern world.