Our phone company has a distinctive ring option that we use for our fax machine. Our monthly service comes with 3 free options (like caller id, call waiting, voice mail... and distinctive ring) We choose a distinctive ring as one of the options. As an extra it costs $3 or $5? per month. It gives you a seperate phone number that doubles on an existing line. When someone calls that number it rings twice. You can set up any fax machine to recognize the double ring and pick up only those calls. So we have 3 phone #s but only 2 lines. We have the double ring on our home line so that faxes don't tie up the business line.