What is a fax line?

A fax line is the phone line or phone number a practice uses to send and receive faxes. A practice that sends faxes from a machine on a phone jack, or from a number on a web account, has one.

How does a fax line work?

A fax line carries each fax from the sending machine to the receiving number. The sending machine dials the receiving number, sends the pages, and reports whether they went through.

Incoming faxes arrive on the line whenever the machine answers. The line works only while the phone service behind it stays active, so a practice should know who holds that account.

A fax number on a web account works the same way for a sender, and it needs no phone jack in the office.

Does a fax line matter for HIPAA?

A fax line matters for HIPAA only through the faxes that cross it, because the line itself holds no protected health information. Any page can hold protected health information, so the paper needs the same care as any patient record.

Pages left on a shared machine can reach people with no need to see them. Staff can collect each page as it prints, and the machine can sit where patients never walk.

For a side-by-side look at the two, see online fax compared with a fax machine.

Is a fax line the same as a fax number?

A fax line and a fax number are different things. The line is the connection that carries a fax, and the number is the address that senders dial.

• Dedicated fax line: a phone line used only for faxes, so a voice call never ties up the line.
• Dedicated fax number: a number assigned to one practice for faxes, which can sit on a line or a web account.
• Cloud fax number: a fax number on a web account, with no phone line in the office.

Your own number comes with every Fax Pigeon plan, so a Fax Pigeon practice has a fax number of its own. For what happens to a number when its line is shut off, see what happens to a fax number when its copper line is shut off.

* Fax Pigeon prices and plan terms as of October 15, 2026.