PSTN Lines – Public Switched Telephone N etwork, which refers to the international telephone system based on copper wires carrying analog voice data. This is in contrast to newer telephone networks based on digital technologies, such as ISDN. PSTN lines are the same for home service and business service, the only difference being when connected to a Telephone System. A PSTN line can connect directly to a handset (s) or other device like a fax. They can also be attached to a Telephone System

Telephone service carried by the PSTN is often called Standard Line or Plain Old Telephone Service (POTS).