The traditional public switched telephone network used for telephone and fax calls, including calls from POTS and ISDN services.
- The PSTN (Public Switched Telephone Network) is the global circuit-switched network that connects landlines, POTS lines, and traditional fax calls.
- A traditional fax call is routed through the PSTN the same way a voice phone call is, using the same switching infrastructure.
- Fax.Plus faxes still reach a traditional recipient through the PSTN when needed, but the sender never has to connect to it directly.
What Is the PSTN?
The PSTN (Public Switched Telephone Network) is the global circuit-switched network that connects landlines, POTS lines, and traditional phone calls to each other, regardless of which local provider or country they're on. It's the infrastructure layer underneath the phone call itself, not a service a person subscribes to directly.
How a Traditional Fax Call Uses the PSTN
A traditional fax call is routed through the PSTN the exact same way a voice phone call is, using the same switching infrastructure to connect the sender's line to the recipient's. This applies whether the call originates from an individual landline, each individual POTS line, or, less commonly today, a digital ISDN connection.
Does Fax.Plus Use the PSTN?
Fax.Plus faxes are sent over the internet on the sending side, but a fax reaching a recipient who still uses a traditional phone-connected machine ultimately completes its final leg over the PSTN, the same way any call to that number would. The sender never has to connect to the PSTN directly, that part is handled entirely behind the scenes. See planning the move from an office analog fax line for more on that shift.
A Common Case: Consolidating Fax Lines Across Store Locations
Consider a large retail chain based in Tennessee with dozens of locations that historically used local telephone connections to fax paperwork to headquarters. It reviews each fax number’s eligibility, staff access and any equipment sharing those services before moving the fax workflow to Fax.Plus. Existing services remain active until any number transfers are confirmed complete and remaining dependencies are addressed. Outside partners can continue using telephone-connected fax machines.
FAQs
Does the PSTN support fax, or only voice calls?
Both. The PSTN was built primarily for voice calls, but it also carries fax transmissions using the same switching infrastructure, since a fax call is routed no differently than a phone call.
Does Fax.Plus use the PSTN?
Fax.Plus sends faxes over the internet on the sending side. A fax reaching a recipient on a traditional phone-connected machine still completes its final leg over the PSTN.
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