This European Standard defines a standardized web service based interface between Home and Building HBES Open Communication System and other information technology (IT) systems. The standardized interface is encapsulated in a gateway device@ the HBES Gateway@ which is able to communicate with both the Home and Building HBES Open Communication System and the connected IT systems. The HBES Gateway implements a set of encoding standards (see 10.2) as well as various message exchange protocols (see 10.3) to enable remote access to the Home and Building HBES Open Communication System via the Internet or another wide area network (WAN). For this purpose@ gateway profiles define different implementation levels (see 10.4).