What is fax?

Fax (short for facsimile), sometimes called telecopying or telefax, is a technology used to transmit documents electronically over telephone lines. A fax machine scans a document, converts it into an electrical signal, and sends that signal over the phone line to another fax machine, which then decodes the signal and prints a copy of the original document. While largely superseded by email and other digital communication methods, fax machines are still used in some industries and situations where a physical copy of a document with a signature is needed, or where digital infrastructure is limited.