Abstract: A cable end connection to a loading coil case has a lead sleeve crimped over the cable end, with a layer of sealing compound between the lead sleeve and the outer protective sheathing of the cable. The metal sheath of the cable is exposed at the cable end by removal of the protective sheathing for a short distance and the end of the lead sleeve is soldered to the metal sheathing. A tube extending from the end of the loading coil case is a close fit over the lead sheath, the outer end of the tube soldered to the lead sheath.

Abstract: A temperature compensated helical resonator structure having a rigid dielectric filling between helix and shield of a material with a negative thermal coefficient of permittivity. The filling provides shock resistance by preventing the helix from vibrating, while simultaneously aiding in thermal compensation.

Abstract: A loading coil assembly comprises a casing having discs at each end. At the inlet end a support disc is mounted on and spaced from the end disc and a plurality of assembled magazines holding loading coils is attached at one end of each magazine to the periphery of the support disc. A similar support disc interconnects the other ends of the magazines, the magazines extending in a circle about the casing axis. Further circles of magazines can be added by providing one or more annular rings attached to the end disc carrying the support disc, for attachment of the magazines at one end, and also interconnecting the other ends of the additional circles of magazines by annular rings. The conductors can be fed along spaces between adjacent magazines. The casings vary in size according to the number of circles of magazines.

Abstract: Accurate alignment between an optical fiber and a light emitting diode -- having a double heterostructure -- is obtained by building the multilayer heterostructure on a substrate surface on which has previously been formed a mesa. After formation of the structure, and forming of a contact on the outermost layer of the structure, in alignment with the mesa, the substrate is etched to form a clearance hole centered on the mesa, which is also removed. The mesa is of the same diameter as the optical fiber and removal of the mesa provides a recess which accurately locates the fiber relative to the light emitting area.

Abstract: A light emitting diode indicator assembly for a multiple pushbutton array has a printed circuit board with a plurality of circuits thereon, each circuit having a connection position for a light emitting diode; a spacer attached to the printed circuit board with a location for a light emitting diode coincident with a related connection position; a light emitting diode at each location with leads connected to the related circuit; a lens over each diode; and a bezel having a first row of apertures with a lens situated in each aperture, and a second row of apertures with a pushbutton in each aperture, the bezel and spacer having interengaging formations whereby the spacer is inserted into a recess in the bezel and the formations engaged by lateral movement of the spacer relative to the bezel. There can be more than one row of lens containing apertures, and also more than one row of pushbuttons containing apertures.

Abstract: A self-closing book holder and support has a back portion, for attachment to a support structure, and two spaced apart forwardly extending wings. Each wing has a forwardly and downwardly inclined top surface, an inner surface and a curved portion blending the top surface and inner surface. A book is normally supported from its top rear edge and hangs down between the wings, the top surfaces of the wings providing support surfaces for the book when held by a user in an open position. On release of the book, the inclination of the top surfaces of the wings and the curved portions, cause the book to close and pivot down between the wings. An enclosure can be provided which encloses the book when in a closed condition.

Abstract: Sputtered thin films, particularly of tantalum and niobium, are prepared having predetermined optical and dielectric properties by controlling the flow rate of O.sub.2 in relation to the flow rate of N.sub.2. By controllably varying the ratio, differing characteristics can be obtained. Thus a stepwise or a continuous variation in refractive index can be obtained. Films show low optical losses and birefringent properties, and are particularly suitable for optical waveguides, capacitors and filters.

Abstract: An optical modulator comprises a metal insulator semiconductor diode having a predetermined reverse bias. In a particular form the modulator comprises an active layer and a confining layer epitaxially grown sequentially on a substrate. In a particular application a monolithic light emitting diode -- modulator structure can be formed.

Abstract: A method of coating a continuous glass fiber filament with plastic, in which plastic is charged into a vertical closed cylinder having a die opening at its lower end and an axial core tube terminating in the die opening to form an annular orifice. The plastic in liquid form is forced through the orifice by pressurized gas introduced into the upper portion of the cylinder while the glass filament is drawn continuously through the core tube.

Abstract: A charge coupled device that provides approximately a fifty per cent increase in storage capacity over the conventional two-phase device by utilizing a multi-ripple technique in which charges are simultaneously stored under three out of every four storage control electrodes.

Abstract: A unidirectional ratchet assembly is located in one arm of a crimping tool so that the tool can be actuated by relatively little movement between the ends of its two arms. The assembly includes a spring loaded pawl which can be disengaged from its associated ratchet wheel so that the crimping tool can be reset without having to spread the arms apart.

Abstract: A variable stripe width semiconductor laser is provided in which, in addition to the contact stripe and back contact, a third contact is provided. By applying a positive bias to the third contact the current spread in the device is reduced, increasing the effective current density at the lasing position. By varying, or pulsing, the applied position bias the current density can be caused to vary above and below a threshold and switch the laser on and off. Further, by application of a suitable positive bias, unwanted higher order modes can be eliminated.

Abstract: A double action switch, for example having both a rotary action and a pushbutton action, is provided with a removable insert which blocks one action while permitting the other. The switch has a frame in which a shaft is supported, for rotational and axial movements. An insert slides into the frame and engages with the shaft to prevent movement of the shaft for one of the actions, while permitting movement of the shaft for the other action. The switch is particularly useful in a telephone unit in which one or more optional operational features are available. The units can be produced, wired and ready for all options, only those required and paid for being available by use of inserts in the switches.

Abstract: A telephone having an interchangeable dial face insert, the insert of transparent material having a shape which fits over an aperture in the dial face of the housing. There is a protrusion on one edge of the insert which enters a slot in the periphery of the aperture in the dial face, and a resilient clip on the periphery of the aperture in the dial face, at a position opposite the slot, the clip engaging over the edge of the insert. A further insert, having information and/or cosmetic patterns thereon, can be positioned beneath the transparent insert.

Abstract: A photodiode detector comprises a substrate on which a plurality of detector sections are formed, in series. Reverse bias is applied to the separate sections, the bias more negative for each section from the input end. The absorption bandwidth for each section can vary and the bandwidth of a section can be variable.

Abstract: Two digitally controllable attenuator networks are provided in the receiver and transmit channels of a loudspeaking telephone system. The analog control signal usually utilized to control the total loop gain in such systems is converted to a digital representation and its complementary representation, one of which is then applied to control the transmit attenuator and the other to control the receive attenuator. Stable, thump-free control of the loop gain is thus achieved.

Abstract: A lighted display for a console, particularly for a telephone console for private branch exchanges, comprises a sandwich structure of a front transparent cover of a dark coloured material, an indicator layer or sheet of dark non-transparent material having transparent characters thereon and a plurality of lamps mounted in holders behind the indicator sheet, a lamp aligned with each character. When assembled an apparently completely dark blank display is presented, but on lighting of a lamp a clear distinct indication appears. Indication characters can be in vertical columns, and there is no need to stagger characters as occurs with conventional displays with "edge-lit" characters.

Abstract: Power is fed from a pair of power supplies to each one of a plurality of load circuits through a distributed power switch. A plurality of switch means are each associated with a respective one of the load circuits for connecting it to one of the power supplies in a primary manner and to the other power supply in a secondary manner. Upon failure of its primary source of power, each switch means is effective for automatically connecting its load circuit to its secondary source of power.

Abstract: A step by step central office serving coin box subsets is provided with a link circuit which on initiation of a call from the coin box sub-set connects the line finder circuit through an auxiliary coin trunk circuit to the central office equipment. This is performed whether or not a coin has been deposited at the coin box sub-set. When the user of the coin box sub-set dials the auxiliary coin trunk determines whetherA. the call is charge or non-chargeB. if the call is charge whether or not adequate coinage been deposited.On this determination the auxiliary coin trunk is freed to serve another call. If the call is charge and adequate coinage has not been deposited the call is interupted by the link circuit. If the call is non-charge or adequate coinage has been deposited, the link circuit connects the line finder directly to central office equipment so the call may proceed.

Abstract: A clamp for a plastic coated optical fibre comprises a tubular portion which is a fairly close sliding fit on the coated fibre and an axially split portion having at least one resilient axially deformable finger. The dimension across the split section is slightly larger than across the other portion. An axially split sleeve is axially slidable on the clamp, and is freely slidable along the tubular portion on to the slit portion. Sliding of the sleeve on to the slit section deforms the finger into gripping contact with the fibre coating and also expands the sleeve. This provides a "backing up" force and also accommodates variations in diameter of coated fibre. More than one finger can be provided, and serrations or other formations can be provided on the fingers.