Abstract: An optical fiber organizer for receiving an optical fiber from one direction and storing loops thereof in a plane substantially perpendicular to that direction, which comprises: a substantially cylindrical block having a port running from an end of the cylinder where it is substantially parallel to the axis of the cylinder to a side of the cylinder such that a fiber within it is directed around the circumference of the cylinder.

Abstract: Polymer blend for insulating electrical wires comprises a first polymer (polyester) having an inherent L.O.I. not higher than 21% and up to 40% by weight of a polyimide-siloxane (PIS) copolymer. Preferred polyesters are polybutylene terephthalate or polyester-ester block copolymers. Preferred wire constructions have core insulation layer of polyethylene or polyester overlaid with jacket of the polyester/PIS copolymer blend.

Abstract: A maintenance termination unit (MTU) for use in telephone circuits. The MTU comprises a switching arrangement which can be connected between sets of terminal equipment in a communications channel comprising a pair of lines. The switching arrangement comprises: a DC voltage window detector circuit which, in use, is connected between the lines and is responsive to a voltage between the lines; and series switching circuits, which, in use, are connected in the lines. The arrangement may also include a shunt switching circuit, which, in use, is connected between the lines. The arrangement includes low pass filters associated with the switching circuits. The DC voltage window detector circuit will actuate the switching circuits when the DC voltage between the lines is within respective predetermined bands, but will not actuate the switching circuits when the DC voltage between the lines is not within the respective predetermined bands.

Abstract: A cable splice case or other article for environmental sealing comprises a composite material having multifilament fibres therein, which fibres are blocked in order to prevent passage of fluid through the material in a direction parallel to its major surfaces.

Abstract: A cable splice case or other article for environmental sealing comprises a composite material having multifilament fibers therein, which fibers are blocked in order to prevent passage of fluid through the material in a direction parallel to its major surfaces.

Abstract: Polymer (preferably polyimide) sheets (10) with laser ablated through-holes plated with metal (20) are used for making electrical conections to specified microcircuits, especially unbumped microchips and Tape Automated Bonding (TAB) articles. Bonding with different melting point materials at opposite ends of the plated holes is disclosed. Preferred polyimides are those derived from polymerisation of 4,4'-biphenyldianhydride and (4,4'-diaminobiphenyl, or 4,4'-diaminobiphenylether, or phylenediamine, preferably p-phenylenediamine).

Abstract: A circuit protection arrangement comprises a series switching circuit that is intended to be connected in a line of the circuit and will switch to an open state when subjected to an overcurrent, and a shunt switching circuit that is open under normal operating conditions but will shunt the overcurrent across the load of the circuit or to ground when triggered by the series switching circuit. Preferably the series switching circuit comprises a switching transistor (4) that is controlled by a control transistor (6), and the shunt switching circuit comprises a shunt switching transistor (9) that is controlled by a shunt control transistor (11) which is itself controlled by the series switching circuit. The shunt switching circuit may be connected to ground or it may be connected to a back-up load or voltage foldback device such as a triac.

Abstract: Gel compositions comprising styrene-(ethylene/propylene)styrene (SEPS) block copolymer having Mw of at least 180,000 and polystyrene content of 25-45 weight percent, and at least 300 parts by weight percent, and at least 300 parts by weight of extender liquid per 100 parts by weight of the block copolymer. The extender softens the ethylene/propylene mid-blocks of the copolymer and the resulting gels have unexpectedly higher tack, temperature resistance, and extender-retaining ability than corresponding gels made with styrene(ethylene/butylene)-styrene block copolymers.

Abstract: A switching arrangement that can be connected in a communications channel comprising a pair of lines, between sets of terminal equipment, which comprises:(i) a pair of series switching circuits, each of which can be series connected in one of the lines and will open when subjected to an overcurrent in its associated line; and/or(ii) one or more shunt switching circuits connected between the lines, or between one or both the lines and earth, and will close when subjected to an overvoltage in its associated line;wherein the or each switching circuit can be remotely actuated by means of a test signal sent along the channel.

Abstract: A recoverable article comprises a recoverable fabric, means for rendering the fabric impervious, and a shaped liner. The assembly can be used to form a pressure resistant splice case for telecommunications cables.

Abstract: Gels made of 100 parts of Styrene-elastomer-styrene triblock copolymers and more than 300 parts of an oil which softens and extends the elastomer mid-block of the copolymer are rendered resistant to oil exudation under pressure by incorporation of a styrene-elastomer diblock copolymer. Preferred triblocks are styrene-ethylene/butylene-styrene and preferred diblocks are styrene-ethylene/propylene. Use of the gels as sealants in enclosures for electrical connections designed to hold the gel under compression is disclosed.

Abstract: An arrangement for protecting an electrical circuit such as a telephone circuit from a voltage transient comprises a voltage clamp or foldback device (3) arranged to be connected between a current-carrying line (1) and ground (1'), a capacitor (2) in series with it, and an inductance (4) series connected in the line. During normal operation the arrangement acts as an LC filter whose high frequency break-point is determined by the capacitance of the voltage clamp or foldback device (3) and the value of the inductance (4) which are chosen to give a break point of 1 kHz to 10 MHz. However, when the arrangement is subjected to a voltage transient, the voltage clamp or foldback device (3) fires causing the break-point to fall to a value determined by the values of the capacitor (2) and inductance (4). The arrangement may be used, for example, to protect the circuit against a rapid voltage drop caused by the firing of another circuit protection device such as a gas discharge tube 5.

Abstract: Article and method of making same by laser-ablation-machining of (a) aromatic and/or amorphous polyamide material, or (b) polymeric material having repeating in its polymer backbone aromatic rings and aliphatic chains (with the proviso that the aliphatic chains have at least 4 carbon atoms when the material is a polyester, and preferably in all cases U.V. laser radiation is preferred, preferably at wavelengths greater than 248 nm from a KrF or XeCl excimer laser. The preferred polyamides, polyetheresters, and polyimides have superior machining performance and may be useful for making uniaxially electrically conductive articles by machining holes cleanly through laminar sheets of the preferred polymers, which sheets are subsequently metal plated.

Abstract: An electrical cable comprises one or more insulated elongate electrical conductors (1,2), a metal electrical shield 5 surrounding the conductors and a pull-thread 7 that extends along the cable under the shield so that the shield can be cut longitudinally by pulling the thread.The cable can be stripped of shield and jacket simply by pulling the thread and then tearing the end of the shield and jacket off. If desired a second conventional pull thread may be located between the shield and jacket in order to allow the jacket to be removed and the shield exposed.

Abstract: A hollow, heat-recoverable article 1, for enclosing objects such as electronic components etc. has a thermoplastic lining on its interior surface and includes a fusion bonded portion 2 in which different parts of the article have been brought together and bonded by fusion of the lining with substantially no welding of the heat-recoverable material forming the wall. The lining has a melting point that is higher than the recovery temperature of the article, thereby enabling subsequent recovery of the article without rupture of the bonded portion.

Abstract: A circuit protection arrangement that is intended to be series connected in a line of an electrical circuit comprises a transistor switch 1 that controls the circuit current and has a control input, and a control arrangement that controls the voltage of the control input of the switch. The control arrangement comprises a comparator circuit 3 that compares a fraction of the voltage across the switch 1 with a reference voltage, for example supplied by a Zener diode or bandgap diode, and opens the switch if the fraction is greater than the reference voltage. The comparator circuit is powered by the voltage drop in the line across the switch so that the arrangement can be formed as a two-terminal device that requires no external power source.The arrangement has the advantage that it exhibits a relatively small variation in performance with respect to temperature variations.

Abstract: A generally-planar polymeric protective shield (2) for mounting on a high voltage porcelain insulator (16) has circumferential and radial intersecting grooves (8,10) in its upper surface. The intersections are deepened to provide point projections (12) from the lower surface thereby to space the major portion of the shield (2) from the insulator (16). The convoluted upper surface of the shield (2) enhances the physical protection of the porcelain of the insulator (16).

Abstract: Gels of hard-elastomer-hard block copolymers with at least 300 parts of extending liquid per 100 parts of the copolymer contain at least 50 parts (per 100 parts of copolymer) of a stabilizing additive which resists migration of PVC plasticizers into the gel when in contact with a plasticized PVC article. Styrene-(ethylene-butylene)-styrene triblock copolymers with organic phosphate stabilizers are preferred, these stabilizers tending to raise the gel softening temperature.

Abstract: A method of sealing a connector (2) in an electrical cable (1) for example a submarine cable comprises:(i) applying a quantity of gel (6) onto the connector and encapsulate at least part of it;(ii) positioning an inner hollow dimensionally recoverable article (9), for example in the form of a cap, about the connector and gel and recovering it thereon to enclose the gel and at least part of the connector, the recovery causing part (12) of the gel to exude out of the open end of the article; and(iii) positioning an outer hollow open-ended dimensionally recoverable article (13) over the connector (2) and recovering it so that it encloses at least the end of the inner article (9) and the part (12) of the gel (6) that has exuded therefrom.This method can enable an effective seal against moisture ingress to be made while at the same time being relatively easy to remove for re-entry without damaging the connector.

Abstract: An arrangement for protecting an electrical circuit such as a telephone circuit from a voltage transient comprises a voltage clamp or foldback device (3) arraigned to be connected between a current-carrying line (1) and ground (1'), a capacitor (2) in series with it, and an inductance (4) series connected in the line. During normal operation the arrangement acts as an LC filter whose high frequency break-point is determined by the capacitance of the voltage clamp or foldback device (3) and the value of the inductance (4) which are chosen to give a break point of 1 kHz to 10 MHz. However, when the arrangement is subjected to a voltage transient, the voltage clamp or foldback device (3) fires causing the break-point to fall to a value determined by the values of the capacitor (2) and inductance (4). The arrangement may be used, for example, to protect the circuit against a rapid voltage drop caused by the firing of another circuit protection device such as a gas discharge tube 5.