Do I need a separate phone line for a fax machine?

Only one telephone line is necessary in order to use a fax machine, though having a separate, dedicated telephone line for the fax machine has distinct advantages. Having two separate lines allows a person to receive faxes while using the telephone and allows faxes to arrive at any time.

If a fax machine is not on a dedicated telephone line and a person answers the phone while a fax is arriving, the person hears a combination of static and loud tones. Likewise, if a person makes a phone call to a line that is connected to a fax machine and nobody answers, the person calling experiences a similar set of sounds.