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). Subdevice status messages are defined whereby a control subdevice can ask to be informed of the status of a further subdevice (e.g. 26), and in particular to be informed automatically of any change in status without the need for continuous polling of subdevices. The subdevice status messages can be used to obtain early confirmation of a signal path being established through the system.

Abstract: A number of domestic audio/video apparatuses (10,12,14) are interconnected by a Domestic Digital Bus (16) for the exchange of control information. A User I/O subdevice (41) in one apparatus is addressable by a control subdevice (22) of another apparatus to allow the display of menu items defined by the control subdevice. The User I/O subdevice returns user control signals by reference to the defined menu items. The right of menu control can be transferred via the User I/O subdevice to and from other control subdevices (20 etc.) to allow integration of the menu control functions of the different apparatuses.

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.

Abstract: A system of domestic video apparatuses (10,12,14 etc.) are interconnected by video cables (64,66,68) and also by a serial data bus (D2B,16) having distributed control intelligence (20,22). Within each apparatus, signal generator and/or detector functions are defined, which can be activated and controlled via the bus (16). The video cable connections (64,66,68) between various plugs (26-1,2,3, 52-1,2,3, etc.) of the apparatuses (10,12,14) are identified automatically by interrupting signal transmission from all apparatuses involved then allowing a single transmission from an input to the connections and detecting the where the signal is output. By repeating the process with other all connections may be traced. The automatic identification of cable connections occurs without requiring additional conductors for cable detection signals.

Abstract: A domestic video system includes a number of interconnected video apparatuses (10,12,14), at least one of the apparatuses including a facility for conversion of the aspect ratio of video signals. The system further includes control signalling (20) operating via a standard serial bus (16) for systematically interrogating each apparatus in a signal path to determine whether aspect ratio conversion is necessary in the signal path and for selectively enabling or disabling any conversion facility in the signal path to effect such necessary conversion. The control means implements a strategy for eliminating unnecessary conversion of aspect ratio in the signal path, and also chooses to effect conversion as late as possible in the signal path when faced with more than one available conversion facility.

Abstract: A public communication system for encrypted audio/video information has various selective entitlement organizations with respect to its distributed receiver station. Such receiver station comprises one or more receiver sub-stations for decrypting the received encrypted information by means of a decrypting key. Furthermore, the receiver station comprises one or more description key sub-stations that may be interrogated by the receiver sub-stations and thereupon may verify a conditional access requirement, and in case of positive verification, forward decryption key information to the interogating receiver sub-station. All said sub-stations are interconnected by a serial standard bus, so that the configuration of a station is flexible and may even be altered dynamically.

Abstract: A public communication system for encrypted audio/video information has various selective entitlement organizations with respect to its distributed receiver station. Such receiver station comprises one or more receiver sub-stations for decrypting the received encrypted information by means of a decrypting key. Furthermore, the receiver station comprises one or more decription key sub-stations that may be interrogated by the receiver sub-stations and thereupon may verify a conditional access requirement, and in case of positive verification, forward decryption key information the interogating received sub-station. All said sub-stations are interconnected by a serial standard bus, so that the configuration of a station is flexible and may even be altered dynamically.