Recently connected to NBN with HFC and using TPG Router (Archer1600v).
Experimented with our fax Machine (Brother 1030e) and achieved a successful connection
FAX/phone device will work on line 1 connecter on the router.Discussion on this forum indicates line 2 connecter on the router is for a separate dedicated number and will not work with a single allocated phone number.
Test fax toTelstra test fax dedicated line 1300 368 999 results in a return phone call (fax shows "pick up phone")but no caller answers(possibly no longer staffed).
Fax machine display shows fax successfully sent.
Combination of NBN HFC with Archer Router and Brother Fax appears to work ,possibly other hardware combinations might be worth a try