This paper proposes using an IPv6 multi-protocol gateway to provide standardized internet access to heterogeneous building automation devices. The gateway maps each device to an IoT-oBIX contract to provide a common representation. It offers web service interfaces for each device, bound to a unique IPv6 address. Evaluation shows CoAP/EXI is most efficient, and remote control delays are under one second. The approach integrates different automation technologies through web services while hiding their differences.