The advertising for this router says "The DrayTek Vigor 2860Vn Plus provides two analogue phone ports and one analogue line port to provide full PSTN and VoIP integration using your Broadband connection and your regular analogue line. The two connected phones can be used either independently or simultaneously for incoming and outgoing calls."

Does anyone know how to do this as I seem to have only one analogue phone port out.

There's an RJ11->2xBT splitter.