First of all, do I understand correctly that Vonage VoIP uses SIP and that the ATA's they supply are "locked" SIP devices? And that Vonage will not divulge its SIP details? (Probably to avoid loads of support calls from consumer-type customers who should never be directly exposed to SIP configuration.)

If yes, then my real question is: Can I re-use/unlock any or all of my Vonage D-Link VTA-VC, Vonage D-Link VTA-CV, and Vonage V-Portal VDV21-VD "orange-stripe" ATA's for generic SIP? Will they still work with Vonage too, and/or will they re-lock in that case?