Abstract: A local communication system has a number of stations connected for the communication of messages by one or more data channels. One of the stations comprises a display device operable to display messages sent by other stations in one or more of a plurality of fields. Each message to be displayed is given a display lifetime (80-84), which is determined by a mode value (74-78) set by the originating subdevice or commonly assigned by the display device. The display determines whether there are sufficient display fields available (68) to display a received message and handles the timing (88) and subsequent removal from display (90) of a message on expiry of its display lifetime, independently of the originating station.

Abstract: In a local communication system comprising a number of devices (14,16) interconnected by a first data bus (20) supporting a first set of communication protocols, and at least one further device (10) connected to a second bus (12) not supporting those protocols, a gateway device (18) is provided linking the first and second data buses enabling communications therebetween. The first set of protocols specifies a maximum time for response by a first device to a request sent by a second device. When a request is sent from a device (14) on the first bus to the further device (10), the gateway (18) times the request and, if no response is received from the further device within the specified maximum response time, the gateway (18) generates and sends a temporary response to the requesting device (14). The system may comprise two or more clusters of devices, each being linked to the further bus (12) by respective gateway devices (18,22).

Abstract: Apparatuses (1,2,3) of an audio/video system convey user commands to one another via a serial control bus (4). The user commands convey key activations on a remote handset (18a), whose keys include both "normal" keys such as "mute/unmute", and "repeat" keys such as "volume up" and "volume down". To convey a repeat key activation, a first control means (12) within one apparatus addresses a key activation message to a second control means (32) within another apparatus. The second control means (32) synthesises locally a repetitive series of user commands, until a key release message is received. The need for repetitive user command messages to be sent via the control bus is thereby eliminated, and the frequency of repetition can be defined locally to give consistent response to user commands. The second control means (32) can also implement a de-bouncing function, disregarding duplicate user command messages sent by a third apparatus (2) which also responds to the handset (18a).

Abstract: A multistation single-channel communication bus system accommodating master stations and slave stations, with any master performing arbitration, arbitration outcome detection, and, upon winning the arbitration, formatting a frame having a slave address and slave control signals, and accommodating data byte periods for data transmission from a transmitter station to a receiver station up to a first maximum data byte length. Each period accommodating an acknowledge bit from the receiver station. The transmitter station responding to the absence of the acknowledge bit for a particular data byte by repeating that data byte. The system, for a message whose data byte length would exceed the first maximum, divides the message into partial messages each of an associated frame data byte count below the first maximum, and assigns each partial message to a respective bus frame. The system counts, in a particular frame, data byte periods and received acknowledge bits.

Abstract: Apparatuses of an audio/video system convey user commands to one another via a serial control bus. The user commands convey key activations on a remote handset, whose keys include both "normal" keys such as "mute/unmute", and "repeat" keys such as "volume up" and "volume down". To convey a repeat key activation, a first control means within one apparatus addresses a key activation message to a second control means within another apparatus. The second control means synthesises locally a repetitive series of user commands, until a key release message is received. The need for repetitive user command messages to be sent via the control bus is thereby eliminated, and the frequency of repetition can be defined locally to give consistent response to user commands. The second control means can also implement a de-bouncing function, disregarding duplicate user command messages sent by a third apparatus which also responds to the handset.

Abstract: A multistation communication bus system including a plurality of master stations and a slave station for transmitting information from the master stations and slave station using a frame based arbitration process. The master station which wins the arbitration transmits a framewise organized message including locking and unlocking signals for respectively, locking and unlocking an addressed slave station, thus blocking any other master station from accessing the slave station for a duration of multiple frames of the message.Any other master station, upon detecting this blocking condition, executes a first sequence of retry undertakings at a combined time length that is substantially less than a standard maximum value of the duration. A second sequence of less frequent retry undertakings at a combined time length that is more than a standard maximum value of the duration may then be attempted.