Simplex vs Duplex. If you are in the process of connecting two devices together and making use of fiber optic cable you’re going to need to understand the difference between these terms in order determine which will work best for your particular setup. To simplify it, it all comes down to the direction in which you wish to send signals between devices.

Simplex 

Simplex communications are sent in one direction, information travels down a  proverbial “one-way street”. As an example, a signal is transmitted via a Simplex Fiber Optic Cable from device A to device B, the signal cannot return from device B via the same cable.

This may seem ineffective but it does come into play within certain networking scenarios and it is fairly common, if not the most common example of modern communication. A prime example of Simplex communication would include that of typical residential internet access. Here a single line (Line A) is used for downloading data while another (Line B) is used for uploading data. This allows for dedicated lines for each and thus enables higher download speeds with fewer send requests being required.

Duplex

Devices that are connected via Duplex are able to send data in both directions simultaneously. A good example of a duplex connection is your everyday telephone line, which allows for communications from both parties at the same time.

Keep in mind, Duplex connections can only connect two devices at a time, thus if multiple devices need connecting together more links will be required. Duplex Fiber Optic Cables are typically available in what is known as ‘zipcord’ format.