I think he might mean using a software to send fax by dialing to a fax number directly rather than going thru some 3rd party service.

Actually, one great function I missed in the old day is using dial up modem as fax modem so I could fax and receive fax with just a computer. Even the antique 9.6kbps modem has that fuction.

I'm always wondering why they don't inlucde this function in the new smartphone so we can fax using the phone or thru computer directly, even we can tether it as a dial up modem, or the fax protocol can't go thru the cellular network?