What is PSTN? How does it Work?

Posted by ryan on January 8th, 2020

PSTN abbreviates for Public Switched Telephone Network, or the traditional circuit-switched telephone network. It is basically a system that has been in general use since the late 1880s. With the use of underground copper wires, this traditional platform has provided businesses and households alike with a reliable means to communicate with anyone around the world for generations.
The phones themselves are known by different names, such as PSTN, landlines, Plain Old Telephone Service (POTS), or the fixed-line telephones. PSTN network phones are widely used and generally still accepted as a standard form of communication. However, they have witnessed a steady decline over the last decade. In fact, there are around 972 million fixed-line telephone subscriptions in use all across the globe, which is actually the lowest tally this century so far.

How PSTN Phone Lines Work?

Just think of a Public Switched Telephone Network (PSTN) as a combination of telephone networks used worldwide, including the telephone lines, fiber optic cables, switching centers, cellular networks, as well as satellites and cable systems. These help telephones communicate with each other.

When you dial a phone number you call moves through the network to reach its destination and then the two phones get connected. In order to completely understand how it actually works, consider the step by step process when you dial a number from your phone:

Step 1- Your telephone set converts sound waves into electrical signals. These signals are then transmitted to a terminal via a cable.

Step 2- The terminal collects the electrical signals and transmits these to the central office.

Step 3- The central office routes the calls in the form of electrical signals through the fiber optic cable. The fiber optic conduit then carries these signals in the form of light pulses to their final destination.

Step 4- Your call is routed to a tandem office or a central office.

Step 5- When your call reaches the right office, the signal is converted back to an electrical signal and is then routed to a terminal.

Step 6- The terminal routes the call to the appropriate telephone number. Upon receiving the call, the telephone se converts the electrical signals back to the sound waves.

So if you need a PSTN network phone system for your business, you will need to have a separate line for each employee. If you need a PSTN for up to 40 employees, your best bet will be to choose a Key System Unit (KSU). This option provides you with several additional features, making it a better choice than a regular telephone connection. It will cost you anywhere between 0 and 0 or even more per line.