Abstract: A cross connect system for telecommunication wires reduces the required time to install and effect cross connections if the wire connections are made by hand and changes are made between circuits by unplugging a modular plug and plugging it in at a different position. The connector of the present invention has a terminal block accepting a plurality of plugs connected each to a pair of wires and the plugs fit onto the terminal block or can be stacked on each other for half tapping, testing or transferring. Protected plugs may be provided having overvoltage protection circuits, and jumper plugs may be stacked onto such protected plugs.

Abstract: A holder for annealing a fiber optic coil uses a silica ring on a silica substrate, or silica tubular coil, either of which may be directly incorporated into a coil subassembly for a Faraday-effect current sensor. The ring may be formed in a silica plate by sandblasting or grinding, or formed separately and adhered to the plate. In the tubular holder embodiment, silica tubes and sleeves are used to protect fusion splices between the ends of the fiber coil and polarizing fibers. Use of silica for most of the subassembly components matches the coefficients of thermal expansion of the subassembly to that of the fiber coil, and also allows the coil to be annealed at extremely high temperatures. Annealing yields fiber coils of lowered birefringence, particularly when used with spun fibers. Ferrules are used to adjust the angular orientation of the fibers with respect to their planes of polarization.

Abstract: A device for tapping an optical fiber is adapted to engage a fiber supporting structure, such as a tray, having an aperture therein and a fiber passing over the aperture, the fiber tray and the clip-on device having a 3-point, nested contact which essentially restricts all relative movement between the tray and the device in the contact plane, providing improved repeatability in the positioning of the optical fiber in the head of the device, and thus improving repeatability of the optical measurements. A similar 3-point, nested contact may be used to align a mandrel housing with a fiber guide in the head, prior to a mandrel engaging the optical fiber. The mandrel housing is slidably received in a cylinder, and may have an elliptical outer surface which fits in an elliptical inner surface of the cylinder, to prevent rotation of the mandrel housing within the cylinder.

Abstract: A family of condenser lenses for an overhead projector (OHP) are designed to balance overall brightness in the projected image versus uniformity of illumination. The lenses are plano-convex and aspheric, and their conic constant is a function of the radius of curvature. The radius of curvature is further selected from a range which depends upon the size of the stage of the OHP. Preferred values of other parameters of the lens and OHP optical system are selected to complement the lens design. The lens is constructed of a heat-resistant material, such as borosilicate, to withstand the high temperatures generated by the incandescent lamp within the OHP base. Condenser lenses which are members of the described family provide performance, in terms of total luminous flux and uniformity of that flux, which is superior to the performance of previous designs.

Abstract: An apparatus for locating obscured conduits, such as buried cables, employs a novel signal processing technique to increase the sensitivity of the apparatus, particularly in congested areas. The cable locating apparatus is similar to prior art dual-peak detection devices which compare signals from two parallel induction coils, but a phase shift is introduced into one of the signals prior to the comparison. This phase shift serves to minimize the effects of side minima in the response curve of prior art dual-peak devices. This effect is enhanced by adding a gain mismatch to the two detected signals. The locator preferably operates with analog signals to reduce expense.

Abstract: A card reader which doubles as a carrying case for storing a stack of preview cards used in an electronic presentation. The card reader case has a flat, rectangular body housing the reader components, and a cover hingedly attached to the body, the cover having a pocket therein for storing the cards. The cover is attached in such a manner that the topmost of the stored cards is visible when the cover is in the open position. In this position, the lower end of the cover also serves to support and elevate one end of the body. The body further has a slot therein on its upper surface for retaining one of the cards for optical scanning, the scanned card extending away from the upper surface so as to be visible to the user during scanning. A discard area may also be formed on the upper surface of the body, and a light source may be positioned on the upper surface to illuminate any card retained in the slot.

Abstract: A fiber optic, Faraday-effect sensing coil has very low linear and circular birefringence, which remains stable over a wide range of temperatures. The coil is fabricated from a spun fiber having an effective linear beat length of 100 meters or more, and is annealed after being formed into the coil. The coil has improved discrimination for magnetic fields associated with electric current-carrying cables, and may be incorporated into an optical current transducer (OCT), either interferometric or polarimetric.

Abstract: A fiber optic housing has a low part count, with all major parts formed by cutting, stamping or bending sheet metal, and with very few fasteners, reducing cost and simplifying assembly of the housing. In spite of the simplified construction, the housing retains great flexibility in the installation of the fibers and associated connectors, primarily due to the provision of a unique chassis which is completely removable from the housing, as well as a backplane frame which is further removable from the chassis. A novel bulkhead plate, and method of attachment thereof to the frame, are also disclosed. The chassis may have a drop center floor to more efficiently utilize space and yet still provide curved surfaces for the smooth exiting of the fibers from the housing.

Abstract: A method of polishing ferrules used in optical fiber connectors centers the apex of the spherical end face of the ferrule on the fiber axis. The invention is directed to ferrules whose ends are angled and generally spherical, providing angled physical contact (APC) between a pair of interconnected fibers. These ferrules commonly have a chamfer from the outermost diameter leading to the spherical, angled end face. In such prior art ferrules, the apex of the spherical end face does not coincide with the fiber axis, leading to a potential gap between the fiber ends, which affects several performance factors, including insertion loss, stability and repeatability. The present invention provides several practical methods for imparting an APC finish to a chamfered ferrule while maintaining the apex of the spherical end face on the fiber axis.

Abstract: A low-profile, transmissive overhead projector (OHP) employs a novel condensing lens system having a catadioptric Fresnel lens and a dioptric Fresnel lens. Each of the lenses exhibits chromatic aberration, but the dispersion of one lens is selected to cancel out the dispersion of the other, e.g., if the catadioptric lens has negative dispersion then the dioptric lens is selected to have positive dispersion. The mutual cancellation of the dispersion of each lens practically eliminates longitudinal chromatic aberration through the lens system. The lens system provides a fast condensing system which allows collimation, dispersion or concentration of light striking the lens at a high angle of incidence. This characteristic is particularly suited for a low-profile OHP as it allows the light source to be placed directly under, but very close to, the stage area.

Abstract: A compact fiber optic housing has a tray divided into front and rear areas by a partition, the rear area receiving excess slack from optical fibers, and the front area having a bulkhead for receiving fiber optic connectors. The front and rear areas overlap to optimize the space within the tray; the tray may consist of a single base supporting the front and rear areas, or of two separate front and rear shelves which are removably attached to each other. The bulkhead includes clips which releasably secure the connectors to the tray, the clips being received in apertures in the base of the tray. A lower tier of the partition slightly overlies the apertures. Each clip is formed from a single piece of sheet metal, having a base for insertion into the apertures, and having a bulkhead riser extending perpendicularly from the base, the riser having a hole for receiving the connector coupling.

Abstract: A low-profile transmissive overhead projector employs a folded optical path and an off-axis Fresnel lens condensing system which includes a catadioptric lens element. This lens provides a fast condensing system which allows collimation, dispersion, or concentration of light striking the lens at a high angle of incidence, with efficient transmission to the far edge of the lens. This also enables additional reduction in the OHP base height by allowing the single mirror to be mounted at a flatter angle, with the light source still maintained at a position below (and adjacent) the stage. A novel catadioptric lens design further imparts achromaticity to the element, so that it may be constructed of any material, regardless of its index of refraction. The condensing system may have a single or doublet catadioptric lens.

Abstract: A circuit tracer for determinating the location of a conductor, such as a wire, which is either an open or closed circuit, and which may lie underground. The tracer includes a transmitter which is connected to the conductor, a hand-held probe, and a receiver which is connected to the probe. The probe has three different sensors: an electric field sensor, primarily for locating the terminus of an open-ended conductor or for distinguishing such a wire in a bundled cable of wires; a differential electric field sensor, for determining the direction to and location of an open-ended conductor located above ground; and an inductive sensor for determining the direction to and location of a current-carrying conductor, including an open-ended conductor lying below ground. A switch selectively provides the output from one of the sensors to the receiver unit, which determines the magnitude of any signal based upon the direction the probe is pointing.

Abstract: An apparatus for reading an optical bar code on a transparent film uses a linear array of light sources and a linear, solid-state sensor located parallel with array. LED's are energized selectively in groups to avoid overlapping shadows on the sensor. A novel algorithm is used to reconstruct the shadowgraphs or image segments by searching for a transition (mark/space edge in the bar code) in an overlap zone at the boundary of adjacent segments on the sensor. Conventional techniques are then used to decode the reconstructed electronic image of the bar code. The apparatus is particularly useful in an electronic presentation system wherein the numeric value of the bar code is an image reference number (IRN) which is used to access a host computer and display a graphic image associated with the IRN. A novel bi-directional protocol is also presented for providing communications between the optical reader and the host computer.

Abstract: An adapter for a conventional conductor locator allows the locator to additionally detect the presence of passive, electronic markers. The adapter includes an electronic marker locator and a wireless interface housed in a common body which may be releasably attached to the conductor locator. The electronic marker locator, which may comprise conventional circuitry, outputs a marker detection signal to the wireless interface, which conditions the signal so that it is compatible with the input sensor of the conductor locator. The wireless interface includes an output antenna which is positioned adjacent the input sensor of the conductor locator when the adapter is attached thereto. If the conductor locator is of the type which may receive test signals at different operating frequencies, then the wireless interface also includes a modulator to selectively convert the marker detection signal to one of these operating frequencies.

Abstract: A testing system for wireless communication networks, particularly cellular networks, having a test set located in a cell site which communicates through the cell's base station to a responder at the mobile telephone switching office (MTSO). The test set, which includes a measurement module, controller, modem, and cellular phone, initiates the call to the responder, and directs the responder to transmit and receive certain test signals which are then measured by the measurement module. The tests preferably include standard "105" tests. The test set, which may be fixed or mobile, provides essentially continuous monitoring of voice channels within a given cell, and can send an alarm in near real-time to the network control center when a faulty voice channel is detected.

Abstract: A combination dust cap and actuation tool for an optical fiber connector having a ferrule and an actuation mechanism for securing a fiber in the connector. The cap/tool has a body with a cylindrical extension having a cavity therein for receiving the ferrule, and a cantilever arm formed on the body, extending parallel with the extension. The cantilever arm has a boss at its distal end for forcibly contacting the actuation mechanism of the connector as the arm is moved in a direction perpendicular to the fiber axis. In this manner, the fiber may be secured to the connector without disturbing the position of the fiber. The cavity has a bottom surface which may have a depression centrally located therein, so that a fiber may be secured in the connector with the terminal end of the fiber extending a known length beyond the ferrule.

Abstract: A fiber optic housing has a low part count, with all major parts formed by cutting, stamping or bending sheet metal, and with very few fasteners, reducing cost and simplifying assembly of the housing. In spite of the simplified construction, the housing retains great flexibility in the installation of the fibers and associated connectors, primarily due to the provision of a unique chassis which is completely removable from the housing, as well as a backplane frame which is further removable from the chassis. A novel bulkhead plate, and method of attachment thereof to the frame, are also disclosed. The chassis may have a drop center floor to more efficiently utilize space and yet still provide curved surfaces for the smooth exiting of the fibers from the housing.

Abstract: A transition joint for sealing an electrical coaxial cable having an oil-impregnated or fluid filled layer. The transition joint has two primary elements, an electrically insulative elastomeric tube and a heat recoverable sleeve. In connecting a paper-insulated, lead jacketed cable to an extruded dielectric cable, the elastomeric tube is placed in tight conformity around the paper layer, slightly overlapping the lead jacket and the central conductor, and further partially overlapping a connector joining the conductors of the cables. The heat recoverable sleeve is then contracted over the elastomeric tube, overlapping the lead jacket and the central conductor, and partially overlapping the connector. The heat recoverable sleeve mechanically restricts the elastomeric tube, preventing the elastomeric tube from swelling which, in turn, precludes absorption of the oil, which would otherwise cause the elastomer to degrade.