Very, very old faxes used to be purely analog. Since dial-up was invented, however, faxes are fully digital. If you've ever used a fax machine, you'll notice th

Very, very old faxes used to be purely analog. Since dial-up was invented, however, faxes are fully digital. If you've ever used a fax machine, you'll notice the classic dial-up handshake noises. Faxes are modems and vice-versa: any PC with a modem could send and receive faxes. It was a commonly advertised feature back in the day.