Abstract: Examples of local communication systems are disclosed, based on a ring of point-to-point links, providing for transport of fixed rate synchronous, fixed rate asynchronous data and variable rate data in a flexible format. Different segments of the ring network can carry data at different bit rates, while remaining synchronized to a common frame rate and having a common control channel structure, for compatibility with earlier systems. Parallel channels are provided, either permanently or when required, for signalling errors of source data, data validity/padding, flow control. Parallel variable width channels are defined with free content (stream or packet). Null data symbols are defined for padding on a byte-by-byte basis. The allocation of capacity among variable width channels is revised block by block, and a transition period is defined to allow for ring latency.

Abstract: A local communication system comprises a plurality of stations exchanging control messages via a ring network. One of which stations is designated a master station with the other stations designated as slave stations. Each of the slave stations has the capability to implement an autonomous process to find and store for future use its own unique address within a set of allowable addresses. Each slave station is arranged only to begin the autonomous process to seek its own address when individually instructed by a command from the master station to do so.

Abstract: A local communication system includes a plurality of stations exchanging control messages and source data via a ring network. One of the stations is designated a master station with the other stations designated as slave stations. On start-up, a “Set Position” message is generated by the master station and modified by each station in turn, so that each station can determine its ring position. In the event that start-up is unsuccessful due to a break down at some point in the ring, the slave station immediately following the break will become temporary master, and will generate a “Set Position” message prior to shut down. By this mechanism, the master station is able to store an indication of the relative position of the temporary master station in the network, so that the fault may be more easily located.

Abstract: A production line irradiation apparatus used to sterilize medical equipment, food or agricultural and waste materials. The apparatus is compact in size and allows a continuous throughput of products to be irradiated, while preventing harmful radiation from escaping. The apparatus comprises: primary shield means for blocking radiation; secondary shield means for blocking radiation; an irradiation device; and conveyor means. The primary shield means further includes a central cavity therein and a channel extending therethrough which intersects the cavity and accommodates the conveyor means. The secondary shield means comprises a plurality of discrete open containers, the containers having front and rear walls, the walls being substantially the size of the channel opening. The walls of the primary and secondary shield means are of sufficient density to fully attenuate the radiation produced by the irradiation device.

Abstract: A local communication system has a number of stations (10,12,13,14) connected for the communication of messages by one or more data channels (16). One of the stations (14) comprises a display device operable to display messages sent by other stations (10,12) in separate ones of a plurality of fields. A station (10,12) sending a display command and message to the user output subdevice (41) of the display device includes field separators identifying discrete parts of the message to be displayed in successive fields of the display and the message portions may be sent as separate messages.

Abstract: A local communication system includes a number of stations interconnected for the communication of messages via a serial data channel. A first station transmits a directed type of message to individual ones of the other stations, or transmits a broadcast type of message to all or a subset of the other stations. For a broadcast message, any receiving station unable to accept the message transmits a common negative acknowledgment signal and the first station re-transmits the message up to five times. Each receiving station may be unable to accept a message because its receive buffer is still occupied by a previous message. In such a case generation of the negative acknowledgment signal is suppressed if the message which cannot be accepted is judged identical to the message occupying the receive buffer of the receiving station. In this way, unnecessary communication is avoided, and certainty of communication is increased.

Abstract: A local communication system has a number of stations (10,12,13,14) connected for the communication of messages by one or more data channels (16). One of the stations (14) comprises a display device operable to display messages sent by other stations (10,12) in separate ones of a plurality of fields. A station (10,12) sending a display command and message to the user output subdevice (41) of the display device includes field separators identifying discrete parts of the message to be displayed in successive fields of the display and the message portions may be sent as separate messages.

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 (M1, M2) sent by other stations in one or more of a plurality of fields (F1, F2, F3). On receipt of a display command and message the user output subdevice of the display ascertains whether there are sufficient display fields available to display the entire message and, if so, allocates display fields to the message. Messages from two or more stations may be displayed simultaneously if there are sufficient available fields, with the user output subdevice allocating an appropriate number of fields to each message.