Abstract: A number of domestic audio/video apparatuses (10-14) are connected to a serial control bus (D2B, 16). Each apparatus is addressable via the bus as a device and contains functional elements addressable on subdevices. One apparatus (14) includes an on-screen display subdevice (41) and a first control subdevice (24). Device information messages are defined whereby the first control subdevice can request a second control subdevice (22) in a second apparatus (12) to compose and return a status message in user-readable form. Thus the user can be informed about status in the second apparatus in an optimum manner, and further can be informed automatically of any change in status without the need for continuous polling of subdevices.