Hylafax (http://www.hylafax.org) is a Linux-based IP fax solution: connected to a phone line via a modem, the software receives faxes and sends them via email to a predefined address as either PDF or TIFF attachments; users can also add a printer to their Windows or Mac desktop and send faxes directly from their desktop applications simply by entering the recipient's fax number.

Sending and receiving faxes over a cellular connection is rapidly becoming a 'black art' as more and more MNOs either drop support for "mobile-originate" or "mobile-terminate" fax altogether, or forget to train their customer services staff on the network's fax capabilities.