Abstract: A method of determining the composition of a polished gemstone comprises passing an excitation beam through the gemstone from a table facet substantially to a culet of the gemstone, an axis of the excitation beam being substantially perpendicular to the table facet; and capturing luminescence emitted by the gemstone from an angle oblique to the axis of the excitation beam.

Abstract: A method of characterising a composition of a gemstone comprises irradiating an upper portion and a lower portion of the gemstone with one or more pulses of ultraviolet radiation at a wavelength of substantially 225 nm or less; capturing luminescence emitted by the upper portion of the gemstone and luminescence emitted by the lower portion of the gemstone in one or more time windows having a predetermined relationship with the or each pulse; and comparing properties of the captured luminescence from the upper and lower portions. A composition of the gemstone is characterised, based upon the comparison.

Abstract: A data processing system comprises a cluster of devices (16) interconnected for the communication of data in streams, particularly digital audio and/or video data. One of the devices (10) is a source device for at feast two data streams to be sent to one or more other devices (12, 14) as destination devices of the cluster. To enable synchronisation of the stream presentations by the destination devices, some or all of the devices (10, 12, 14) carry respective tables (11, 13, 15) identifying, for that device, an identifier for each type of data stream that the device can process together with the processing delay for that stream. The or each such table is accessible via the cluster connection (18) to whichever of the devices, at source, destination or in between for the signal, is handling application of the necessary offsets.

Abstract: The invention relates to a protocol for communications between networked devices. The devices are logically arranged as a hierarchy of device types including a controller device type (52) from which no other device type depends and a basic device type (54) from which a number of other device types depend. The devices implement a simple device description message of fixed length and format which includes the device type, and some devices further implement an extended device description message including additional information.

Abstract: The invention relates to a protocol for communications between networked devices. The devices are logically arranged as a hierarchy of device types including a controller device type (52) from which no other device type depends and a basic device type (54) from which a number of other device types depend. The devices implement a simple device description message of fixed length and format which includes the device type, and some devices further implement an extended device description message including additional information.

Abstract: The invention relates to a protocol for communications between networked devices. The devices are logically arranged as a hierarchy of device types including a controller device type (52) from which no other device type depends and a basic device type (54) from which a number of other device types depend. The devices implement a simple device description message of fixed length and format which includes the device type, and some devices further implement an extended device description message including additional information.

Abstract: A local communication system comprises a first cluster (10) of devices interconnected for the communication of messages via a first data bus (18) and in accordance with a first set of communication protocols, a second cluster (20) interconnected via a second data bus (28) and following the first set of communication protocols; and a data channel (41) linking a device (19) of the first cluster (10) and a device (29) of the second cluster (20). The data channel (41) suitably comprises an RF link supporting communication of messages in accordance with a second set of communications protocols. A device (19) of the first cluster (10) holds a stored software representation of operational features of a selected device (DVHS-2) of the second cluster (20) and any device (11) of the first cluster wishing to interact with said selected device (DVHS-2; 22) instead interacts with said stored representation.