Nowadays home automation systems integrate many devices from security system, heating, ventilation and air conditioning system, lighting system or audio-video systems. Every time a new device is installed, problems with connecting it to other devices and synchronization may appear. The technology trends are to build more powerful and functional new autonomous devices, rather than improve device synchronization, data and functional distribution and adaptation to changing environment. This paper highlights interoperability problems in pervasive computing and presents a solution for devices with limited processing capabilities by use of an ontology for knowledge formulation and semantic interoperability.