Yes, you need to have a fax machine that supports the additional Phone and Faxline feature for your landline.

Phone and Faxline gives you an additional phone number on the same line. Calls to this additional number go to your usual line, but with a distinctive ring that you can set when you set up the service with us. Your fax machine needs to be able to detect that ring to answer.

Voicemail does not distinguish between the two rings. It will simply pick up calls after a certain number of rings. The trick is to set voicemail to pick up after more rings than the fax machine. If the fax picks up after four rings, set voicemail to pick up after six.