Abstract: A data indicator is disclosed which comprises a non-volatile memory (26), control circuitry (24) by which data can be read from and written to the memory, a timer (28) and/or an event detector (30), means such as a terminal (20) for connection to an electrical supply of a host apparatus and an interface (32) through which data can be exchanged with the memory (26). In use, the event detector (30) detects when the host apparatus is switched on and in dependence on the detector output the control circuitry (24) maintains a cumulative history of host apparatus activation which is stored on the memory (26). The data indicator can store other data relating to the host apparatus, e.g. a service interval, and can supply this in conjunction with the actuation history, making it conveniently possible e.g. to establish whether the host apparatus requires servicing. (FIG. 4).

Abstract: An aircraft lighting system is disclosed in which conventional visible light sources at the exterior of an aircraft are provided with optical filters which block infra red light. In this way, it is made possible to use visible external lighting (required by Civil Aviation Authority regulations) during training exercises involving infra red sensitive night vision goggles, which would otherwise be dazzled by the infra red output of the visible lighting. Also disclosed are means of selectively controlling both visible and I.R. light sources using a single existing cable.

Abstract: An identification device comprising an IR LED contained within a housing which is adapted to be carried externally by a person or object who or which is to be identifiable in dark conditions. In cases where the device is to be used as a personnel identification beacon (PIB) the housing can carry means to enable it to have a "stick-on" capability whereby the housing can be easily attached or detached to/from the external clothing of a wearer. The IR LED can be adapted to flash and this can be in a coded sequence to enable the particular wearer to be identified.

Abstract: A sealed LED lamp housing includes a single unit made of a semi-transparent polymer of neutral optical density having a first portion forming a lens, through which light can pass from an LED contained therein, and a second portion, of greater thickness than the first portion, that provides a contrast annulus surrounding the lens.

Abstract: A sub-sea fiber-optic cable location indication apparatus wherein a small portion of a light signal carried by a main optical fiber cable is tapped off and is used to trigger or control a parameter of an electromagnetic, or acoustic signal radiated by a transponder carried by the main cable.

Abstract: An indicator lamp comprising a tubular housing which is closed at one end and has a light source disposed within it at a position remote from its open end. A diffusing screen is disposed within the tubular housing in front of the light source and again remote from the open end of the housing. The internal surfaces of the tubular housing between the location of the light source and the open end of the housing are blackened. A transparent lens is disposed adjacent the open end of the tubular housing and carries on its side closest to the light source an infra-red suppressing filter, and, on its side remote from the light source, an anti-reflection coating.

Abstract: A multi-way connector incorporating an integral filter array and comprising a metal outer casing; an inner housing in the form of a solid block of an electrically insulating material disposed within the outer casing; and a plurality of electrical contacts (plugs or sockets) having lead-through terminations which extend through the housing block, the free ends of said terminations extending from the block carrying respective filter capacitors whose outer electrodes are connected electrically to a metal ground plane which is itself connected electrically to the metal outer casing. Disposed around each lead-through termination is a respective collet which is received within a respective recess in the housing block so as to firmly grip that termination (100) to relieve same of mechanical stresses during connection of a mating connector part with said contacts.

Abstract: An electronic recorder is disclosed which acts as an elapsed time indicator for monitoring the operation of at least one item of equipment and providing display or other indication of the total time for which the item of equipment has been energized. The recorder includes a solid-state oscillator and a divider which together constitute a time-base for producing clock pulses only when the item of equipment is in an energized state. A solid-state counter counts the clock pulses and a solid-state memory stores information corresponding to the counter total. So that the recorder can retain its cumulative total count even when de-energized with the item of equipment, the memory is of the non-volatile type which retains its stored information even when de-energized. A solid-state display means displays the counter total to provide an indication of the total time for which the item of equipment has been energized.