
The traditional analog phone-line service landlines and legacy fax machines run on, defined plainly.
POTS (Plain Old Telephone Service) is the traditional analog telephone service that runs over copper wiring, the same basic connection a home or office landline uses. It carries only one call at a time and is maintained by a local telephone provider rather than an internet provider.
These three terms describe related but distinct things: POTS is the specific analog service type, ISDN's digital circuits are a separate digital alternative to it, and the public telephone network it connects to is the larger switched network both eventually route through.
A POTS line is the connection type most legacy fax machines were built around, since the tones a fax machine sends and receives are designed for exactly this kind of analog circuit. Fax.Plus replaces the POTS line entirely: sending and receiving a fax happens over an internet connection, with no dedicated analog circuit or per-line charge involved. An office that switches its phone service to VoIP without adopting Fax.Plus would still need an adapter bridging the old analog hardware to the new line just to keep a legacy fax machine working, a step Fax.Plus skips entirely. For the specifics of how that line works and what it costs, see exactly what a POTS line is and how it's billed.
A Common Case: One POTS Line Doing One Job
A mid-size consumer services company in Ohio discovers it's still paying for a POTS line dedicated entirely to a fax machine nobody in the office actually uses anymore. Replacing that line with Fax.Plus keeps the same fax number reachable, without the standalone analog line or its recurring bill.
POTS is the specific analog phone service delivered over copper wiring. PSTN is the larger circuit-switched network that POTS lines, along with other connection types, route through to reach their destination.
No. POTS is a specific analog service type, while ISDN is a separate digital alternative that carries voice, data, and fax over the same digital circuit.
