AX522 2 line Intelligent VoIP / PSTN Line Switch
[COOL-AX522]

Does exactly what it says on the tin! Works perfectly with our Vonage and BT lines. I've set our Vonage line as the default, since all outgoing calls to landlines are free. :) I wasn't expecting the Caller ID to work but it does! I had to get a modem cable in order to hook it up to the BT line, but apart from that, it's perfect! :D
--Wellard.