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

What is the use of PSTN?

A PSTN lets users make landline telephone calls to one another. A PSTN is made up of switches at centralized points on a network that function as nodes to enable communication between two points on the network. A call is placed after being routed through multiple switches.

How does PSTN work?

It works by using underground copper wires that are hardwired from homes and businesses to switching centers—where the phone calls are connected to each other. The PSTN carries your voice calls from your telephone (whether that's a landline or cell phone) through the network to the recipient's phone.