Abstract: A rectangular loading coil case has front, back, side and end panels, with cable entry and exit provided in one end panel, and with a support structure attached to, for example, the front panel and comprising rods extending across the case with a series of beams extending in opposed pairs and supported on the rods by spacer members positioned on the rods. Assembled magazines of loading coils are supported on the beams, each magazine supported at one end by one of a pair of beams and supported at the other end by the other of the pair of beams. A plurality of magazines are carried by each pair of beams, to form a layer. The number of layers can vary.

Abstract: A miniature electrical relay, particularly for telecommunications systems, has the armature releasably attached to the armature hinge spring by arranging for the armature and hinge spring to be of U formation, the ends of the legs of the armature and hinge overlapping, and with projections on one of the sets of legs engaging in recesses in the other set of legs. This avoids brazing or other more permanent ways of attachment and reduces fatigue fractures.

Abstract: An electric cable having a multi-stranded core and a jacket, in which the voids between and around the core are at least partially filled with a mixture of a hydrophobic powder and a hydrophilic powder. The hydrophobic powder may be coated calcium carbonate and a hydrophilic powder may be polyacrylamide, in which case the polyacrylamide should be between 8% and 30% by weight of the mixture. Preferably the individual conductors are coated with a hydrophobic oil such as a low viscosity paraffinic oil.

Abstract: An insulation slicing terminal, stamped from electrically conducting sheet material, has a base portion and two cantilevered legs extending from the base portion providing opposed side edges between which a conductor is positioned. The top edge and side edge of each leg intersect at an abrupt angle to form insulation slicing edges, the two top edges forming a shallow Vee formation. An initial small gap is provided between the side edges by a first swage on one leg near the junction with the base portion. A further swage on one of the legs nearer the top of the leg acts to prevent movement of the conductor out of the terminal once the wire is inserted past the further swage. As a further feature, the shallow Vee formation, of the top edges, has an apex prior to slitting which is a radiused flat, permitting off-center tolerances on slitting without detrimentally affecting the insulation slicing edges.

Abstract: An electric cable having a multi-stranded core of insulated conductors and a jacket, in which the spaces between and around the conductors are at least partially filled with a mixture which forms a blockage to the penetration of water. The mixture comprises water repellant treated calcium carbonate and high molecular weight polyacrylamide resin which do not react with each other or when in contact with water. Preferably the individual conductors are coated with a hydrophobic liquid such as a low viscosity paraffinic oil.

Abstract: Loading coils for communications cables are preloaded into magazines and prewired to terminal strips carried on the magazines. A magazine comprises a length of material, typically extruded or molded plastic material, of a channel shaped cross-section to accommodate the coils flat and side-by-side. End caps fit on each end of the magazine to retain the coils in position and also serve as mounting means in a casing. The terminal strips are mounted on an extension of one wall of the channel shaped cross-section. The preassembled magazines are then assembled in the casing a higher packing density is obtained, and the prewiring of the coils to the terminal strips provides effective orientation of the coils relative to each other to give good electrical and electronic separation and reduced cross-talk.

Abstract: An active filter which utilizes a single operational amplifier in conjunction with a plurality of resistance-capacitance (R-C) elements, to simulate either an inductance-capacitance (L-C) or a resistance-frequency dependent negative impedance (R-D) network, in which only one impedance constraint must be met in order to realize the network.

Abstract: Fraudulent toll telephone calls are detected by the recognition of extraneous supervisory signals which are generated in the originating office in response to a perpetrator placing such a call. The invention provides a means of detecting a second proceed-to-send signal received at the originating office and of recording in memory means the identities of the calling and called parties. Timing means for achieving the detection is connected to the automatic message accounting trunk circuit of the originating office and, upon detection, an MF receiver is also connected thereto for a predetermined interval of time.

Abstract: A push-button switch has a spring contact plate and a circuit board in superposed position. The spring contact plate has one or more switch positions, each switch position comprising a prestressed domed portion surrounded by a common flat sheet portion. The spring contacts of each prestressed dome portion selectively engage peripheral contact areas on the circuit board followed by the central contact portion engaging subsequently with a further fixed central contact area on the circuit board. Accordingly, plural inputs of electronic logic circuits may be preselected prior to simultaneous activation upon subsequent closure of the central contacts at a given switch position. Release of the push button enables the domed portion to snap back to the stable position.

Abstract: An open switching interval protection circuit for maintaining continuity on a telephone line during the switching interval of the central office equipment, in which an auxiliary battery voltage is bridged directly across the telephone line under timed control. With such an arrangement the need to break into the talking path or to tie up additional control circuitry in the central office is avoided, thereby providing high reliability at reasonable cost.

Abstract: A high-pass notch filter with variable gain that may be greater than unity is realized using a differential amplifier and only two capacitors that can be equal. The transmission zero and pole frequency are completely independent of the amplifier d-c gain. Three embodiments of the filter are illustrated, thus extending the available range of the gain to cover all requirements.

Abstract: The chromatic pulse dispersion of a light beam in an optical fibre can be equalized by dispersing the light beam into a spectrum, detecting different portions of the spectrum and producing signals related to each portion, applying different time delays to the signals and then combining the signals to provide an output. The spectrum can be divided into discrete portions having a range of wavelengths, with optical delay lines, optical filters, and multiple section photodetectors used. The spectrum can be formed on one surface of a PIN diode, having the I layer of a thickness which varies along the length, giving in effect division of the spectrum into an infinite number of portions.

Abstract: A test set, as used for indicating line conditions and line identification for telecommunication cables for example, has a casing formed from two identical mouldings. A rib and groove seal is provided for the mating surface by forming a rib on half the mating surface and a groove on the other half. Laterally extending webs form a channel in which the leads of the test set are wound when not in use. Ears on the webs extending towards each other form constrictions which maintains the leads in the channel. At the top of the casing, arcuate webs provide a protected region in which are situated a toggle switch and indicator lamps. Inside the casing, formations hold a printed circuit board and define a compartment for a battery.

Abstract: A region of opposite conductivity is diffused into the substrate of a charge coupled device adjacent the edge of one of its storage electrodes and the following transfer electrode to provide an improved structure for nondestructively sensing mobile charges being transferred along the device. With this arrangement there is less capacitive coupling between the region and the electrodes and less disruption of the CCD channel which results in a much reduced perturbation of the mobile charges.

Abstract: A pair of interchangeable memories is provided, one of which receives a PCM frame while simultaneously transmitting one, while the other of which, containing the previous frame, outputs the channel bits for parallel processing. Each simultaneous conference is assigned a temporary storage location in which the associated channels are accumulated to yield the total conference signal. Subsequently, each channel is subtracted from its conference total to produce the final conference signal. The final conference signals replace the unprocessed frame in the memory where, at the end of the current frame, it is interchanged with the other memory. And so on.

Abstract: A method of jacketing an electric cable having a corrugated metal sheath, in which the sheath is cleaned, a coating of thermosetting, castable polyurethane is applied to fill the troughs in the corrugations, a fabric is wrapped onto the coated sheath and coated with the same polyurethane, and thermoplastic polyurethane is extruded onto the cable to form a jacket. The coatings of the polyurethane serve as an adhesive for bonding the jacket to the metal sheath. A cable produced by this method comprises a layer of fabric circumscribing the corrugated metal sheath and a jacket of thermoplastic polyurethane overlying the sheath, the fabric being embedded in a layer of thermosetting, castable polyurethane bonding the jacket to the sheath.

Abstract: A light emitting diode structure has one or more convex lens formations formed on the surface through which the light issues to provide larger incident angles and reduce internal reflection. Conveniently the structure comprises a multi-layer epitaxially grown structure, and the lens or lenses may be formed integral with the outer surface.

Abstract: For a reversed bias double heterostructure diodes, particularly GaAs diodes, electroabsorption can be obtained with reverse bias and light emission can be obtained with forward bias. However bulk absorption is large at wavelengths close to the band edge, where light emission occurs. Thus light emission through a modulator at zero bias is low. By providing for the light emulsion to be at a larger wavelength than that corresponding to the band edge high modulation efficiencies can be obtained. This is achieved by suitably doping the emitter differently as compared with the modulator so that light emission occurs at wavelengths greater than that at the fundamental energy gap.

Abstract: A connector comprising a tubular connecting member having a bore which fits over a coated fiber and having a section which is preformed by deforming the walls of the member inwards to define a smaller central bore which is a close sliding fit on an uncoated fiber. Two coated fibers are connected by the uncoated fibers ends being inserted into the preformed section, a fiber from each end, until in end to end relationship. For a splice, a single connecting member is used and after insertion of the fibers, the ends of the member are crimped on to the coated fiber. For a releasable connector, the preformed section is toward one end of the connecting member which is crimped on to one coated fiber. The other fiber is crimped into a further tubular member with the uncoated fiber extending from the end for insertion in the preformed section of the connecting member. The connecting member and the further tubular member are held in axial alignment by a housing.

Abstract: In a device for filling the interstices of the multi-stranded core of a cable, a die freely rotatable about an axis and having a plurality of passages opening from each end of the die, the passages being arranged in a cylindrical locus about the rotational axis of the die. The device itself consists of a housing defining a chamber holding filler material through which the core passes, one end of the housing being closed by the die and the other end of the housing having an aperture axially aligned with the die.