Because a regular analog line rides on a separate channel along with the DSL circuit, you can still use a fax machine, a modem, an answering machine, etc. You can still do any of the things you do today over your phone circuit.

However, that analog traffic will tie up the voice line portion of a DSL circuit. For instance, if you have an outgoing fax on the voice line, you will not be able to accept an incoming call. In other words, it's just like the situation today.

The difference is this: even if you're on the phone with a voice call or a fax, you'll be able to have high-speed connections to the net at the same time. The high-speed data channel runs over a different channel on the phone wire.

You will be able to use all your existing phone gear without a change.