Abstract: An optical fibre gland for a submerged repeater comprising an insulating body (1) having a bore (4) accommodating a pressure tube (5). A high pressure end fitting (8) is secured to the tube and the body and a low pressure end fitting (12) is secured only to the tube. The tube and fibres are water and gas blocked and the construction is such as to enable the gland to operate satisfactorily over a wide temperature range.

Abstract: An optical repeater for an undersea telecommunications system has a tubular casing (1) closed by a bulkhead (2) with a tail cable gland (2a) providing a common feed through for electrical power conductor (39) to power the regenerator and for optical fibres (28) for optical intelligence signals. Then the electrical power conductor and optical conductor are fed through separate glands ((40) and (32)) which facilitates manufacture and individual pressure testing prior to assembly in the regenerator.

Abstract: A demountable plug/socket connector assembly for making an electrical connection across a high pressure differential between the surfaces of a bulkhead such as the housing wall of a submarine repeater. One sub-assembly, ordinarily the socket sub-assembly is mounted in a bore or aperture on the low pressure side of the bulkhead, the mounting being resilient so that a small amount of engagement overtravel of the mating plug sub-assembly inserted through the bore resiliently disengages a seal between the socket member and the bulkhead to permit the inert gas on the low pressure side of the bulkhead to flow into the interface volume surrounding the pin/socket connection effected by mating of the plug/socket assembly. A second seal enables as the plug member is firmly seated, to exclude the high pressure medium (sea water for example) from entering the interface volume. The operation of the seals is reversible upon detachment.

Abstract: A high pressure gland for optical fibres and/or electrical conductors has a tubular member through which the fibres/conductors are loosely passed. The bore of the tube is then filled with an encapsulating plastics material which adheres to both the fibres/conductors and the wall of the tube bore. The outside of the tubular member is shaped so as to be mechanically secured and sealed in an aperture in a bulkhead or the like. The construction of the gland is such that it can withstand a high axial pressure differential such as might be experienced on the sea bed.

Abstract: A fiber optic cable has a central strength member formed by a wire with helical grooves in each of which is laid an insulated optical fiber. Steel wires are wound over the strength member plus fibers with the direction of lay of the wires opposite to that of the helical grooves so as not to crush the fibers. Also described is a jointing technique for a pair of such cables.

Abstract: A submerged repeater or equalizer housing having a clamping ring therein which dishes and resiliently presses a bulkhead toward an annular seat to compress a seal therebetween. A modified cable outer conductor connection to the bulkhead improves high frequency return loss.