What is PSTN?

PSTN stands for public switched telephone network, which in simple terms is the phone network that enables landline phone service. The PSTN has been in place since the early days of telephones and is operated by a combination of local, regional, and national phone service providers. The PSTN uses copper wires to carry analog or digital voice data and relies on a network of switching centers to act as nodes that carry calls from one local station to the next until the calls reach their final destinations. It can also be used to access the internet, but it's a slower option than broadband.

Cellular service has sent PSTN use into a decline as more consumers opt to use mobile phones rather than landlines. However, many businesses still connect their phones, private branch exchanges (PBXs), and automatic call distributors (ACDs) to the PSTN.