What is Public Switched Telephone Network (PSTN)?

The Public Switched Telephone Network is a compilation of all the public circuit-switched telephone networks in the world, allowing all phones to communicate with one another.  

It’s made up of various components, including telephone lines, fiber optic cables, switching centers, cellular networks, and satellite systems. 

Telephones operating with the PSTN are known as landlines or fixed-line telephones, and they transmit audio through underground copper wires. 

PSTN has been the premier public telecommunication system since the late 1800s, with various local, national, and international carriers supporting it. Today, it’s becoming a legacy platform with the rise of digital communication, but supporting it is still necessary for many businesses. 

What are the benefits of PSTN? 

PSTN is still widely in use today. Some of the biggest benefits include: 

  • Reliability: PSTN operates independently from an Internet connection and still works during a power outage, unlike VoIP, PSTN works well for emergency calls, fire and medical services, and security systems for this reason. 
  • Security: Like any Internet-enabled technology, VoIP still comes with cybersecurity vulnerabilities. PSTN is fairly impervious to such attacks, though it’s still possible to intercept communications through wiretapping if someone has physical access to the copper wiring. 
  • Availability: Some regions of the world don’t have IP-ready infrastructure to support VoIP reliably yet, so PSTN remains popular in these areas for now. 

How does Sinch work with PSTN? 

Sinch offers companies direct access to the PSTN through voice services, including Operator Connect and Direct Routing for Microsoft Teams, toll-free voice, SIP-trunking, and other solutions supported by our Voice API.