Facsimile transmission is the process through which documents are scanned, digitally encoded, transmitted, and decoded for printing on the other end. Fax on demand is a system by which callers can request documents or information through use of a touch-tone telephone pad, and documents are faxed to numbers indicated by caller.

On voice-response systems, a feature that allows a caller to listen to a recorded message, and then select which information they want to have automatically faxed to.

A system that enables callers to request documents, using their telephone keypads. The selected documents are delivered to the fax numbers they specify.