Abstract: A switch assembly is provided for a tape drive adapted to receive a tape cartridge. The assembly comprises a housing, first and second switches fixedly mounted on the housing, and first and second plungers mounted for reciprocal movement on the housing to actuate the first and second switches, respectively. The housing includes three orthogonal reference surfaces, all of which engage the tape drive to locate the assembly in proper relationship to the tape drive. The plungers are responsive to the tape cartridge to actuate the first switch when the tape cartridge is properly mounted on the drive and to actuate the second switch when the tape cartridge is not write-protected. The assembly may include a light source and a light-responsive switch which, together with a reflector in the tape cartridge, cooperate to detect position-indicating tape apertures.
Abstract: A coupling circuit for coupling a printer to a meter permits single line digital printout of metered data in response to operation of a manual switch. Printing is initiated when a bistable occupies one state and a print command is produced by the meter indicating that a stable voltage has been detected by the meter. That bistable state is produced by manual operation of a switch, such operation also triggering a hold unit within the meter to hold the stable reading for a period permitting data to be shifted to the printer and for printing to occur. While printing and paper advance is under way, the printer delivers a busy signal to the bistable to change its state. Subsequent state reversal can then only take place on manually operating the switch once again. In this way only a single line of print is achieved on command. The particular logic arrangement described prevents erroneous printing of lines of data in response to switch contact bounce.
Abstract: A piezoceramic device has two layers of piezoceramic material bonded together, the layers polarized in opposite directions. The device is used to detect, and indicate, a change of voltage between two conductors and specifically is used between the tip and ring lines of a telephone line having more than one extension, to give a line status indication. A visual, yet non-electrical, readout of one polarity is provided when the bending piezoelectric element moves into a window in the housing wall.
Abstract: An aerial terminal has a housing divided into back and front compartments by a dividing wall which has a zig-zag formation from top to bottom. A top section of the dividing wall is set forward from a bottom section and a row of apertures is formed in each section. In a preformed arrangement the apertures are oblong and inclined towards each other in pairs. Terminals having shanks fitting in the apertures have transverse holes orientated by the apertures, to be also inclined towards each other in pairs. Shrouds surround the terminals and a channel in each shroud acts to guide a drop-wire conductor into the related terminal hole. The conductor is fastened by a screw in the front of the terminal. Conductors of a stub cable are attached to the rear portions of terminals extending into the back compartment, and the back compartment is filled with potting compound, which holds on a back cover. A front cover clips on to close the front compartment.
Abstract: A servo track following system for positioning a moving read/write head relative to a magnetic storage disc. A plurality of servo tracks are recorded in sectors on the disc for identifying radial positions or informational tracks. The servo tracks have a nonuniform radial track density varying from more dense at the periphery of the disc to less dense at the interior, established with a method that allows the unique performance characteristics of the head to determine the actual spacing of the tracks. A clock track is written by writing a single pulse on a fixed clock track head, phase-lock looping to an intermediate clock track, which is written on a moving head, and then phase-lock looping up to the final clock track which is written on the fixed clock track head. Radial track density is then determined by moving a head to a limit stop and writing a reference track.
December 14, 1981
Date of Patent:
November 8, 1983
Northern Telecom Inc.
Theodore A. Oliver, David L. Nelson, Keat-Lye Chan
Abstract: A gas tube overvoltage protector has two opposed electrodes sealed in a tubular dielectric housing, the outer ends of the electrodes extending from the housing. The inner ends of the electrodes define a primary gap at sub-atmospheric pressure. The lower electrode has an extension of reduced diameter on its outer end. An auxiliary gap is formed by pushing on a metal cap over the lower end of the dielectric housing, with a thin flexible dielectric member between the cap and the outer end of the bottom electrode, the extension extending through the dielectric member and cap. One or more apertures in the thin dielectric member define the auxiliary gap, between metal cap and bottom electrode. A further feature is that the cage, within which the protector is positioned, has one or more legs preformed such that their lower ends are pushed into positive contact with the metal cap when assembled into a closed ended hollow cap for assembly into a protector block.
Abstract: A compensator for CRT deflection yokes and the like comprises a housing shaped for connection with the deflection yoke, and at least one magnet rotatably mounted therein. Selective rotation of the magnet alters the electromagnetic field produced by the deflection yoke to alleviate distortion in the CRT display. A detented spring arrangement positively and releasably retains the magnet in a set, adjusted angular position in the housing.
Abstract: In a semiconductor wafer processing apparatus, the support rails carrying the boats holding wafers are at least partially supported during insertion into and withdrawal from the furnace by one or more tiltable support brackets. Each bracket has two spaced pillars connected at their bases by a first member which is hingedly connected to a second member attached to a base surface of the furnace apparatus. A rotatable shaft extends between the top ends of the pillars. A projection extends from the first member. In use, as the furnace end plate is moved toward the furnace tube, pushing in the rails, the end plate folds down the, or each bracket as it contacts it. The projection passes up behind the end plate on folding down of a bracket. On reverse movement of the end plate, away from the furnace tube, the end plate contacts a projection and tilts up the related bracket. If a plurality of brackets are provided they are successively tilted up, back to a support position.
Abstract: A fixed count terminal provides an enclosed housing for the connection of service wires to telephone conductors contained in a communication cable. The fixed count terminal has a support bracket which is clamped to a support strand portion of the communication cable with a mounting bar extending between the points whereat the support bracket is clamped to the support strand. A cable portion of the communication cable is clamped to the support bracket by Z-shaped brackets and ground clamps and a tension bar extends between the Z brackets. A barrier wall divides the fixed count terminal into terminal and cable compartments and has a plurality of breakaway partitions which can be removed so that terminal modules may be positioned on the barrier wall. A base is also secured to the support bracket at the bottom of the barrier wall and has grommeted openings through which the service wires may be extended into the fixed count terminal and coupled to conductors in the communication cable via the terminal modules.
December 12, 1980
Date of Patent:
June 28, 1983
Northern Telecom, Inc.
Louis Suffi, James E. Golden, Frederick W. Burtelson
Abstract: An input voltage is converted into a logarithmic representation thereof by exponentially changing the charge of a capacitor, producing pulses at a rate dependent upon the time taken for the charge to change between the two reference voltages, and counting the pulses during the time taken for the charge to change between the input voltage and a reference voltage, whereby the conversion is independent of the precise time constant governing the exponential change. The pulses can be produced under the control of a phase-locked loop, or by frequency-dividing clock pulses by a count which has been previously established by frequency-dividing the same clock pulse frequency by a predetermined factor. The conversion can be effected rapidly and accurately for input voltages within a relatively large range, without using high-precision components.
Abstract: A modulator switch, adapted for telecommunication purposes, has a hollow body within which are a plurality of cantilever contact members, there being a center contact member and at least one side contact member. The center contact is biased towards one side or the other and has an extension actuated by an actuator rotatably mounted on the body. Actuation to make, break or transfer contact can be provided. The switch can be designed for sliding on a cover or another switch. The particular selection of two, or three contacts provides the particular actuation required.
Abstract: Apparatus is provided for eliminating manual completion of tickets by operators at operator positions, one or more of which are operator cordboard positions, of a telephone exchange. The apparatus comprises a keyboard and display unit and an independently operable processing and storage unit provided individually for each operator position, the operator position and keyboard and display unit being connected to the processing and storage unit. Each operator position functions with its associated units independently of the other operator positions and any central processing unit. All of the processing and storage units are coupled via a concentrator to automatic message accounting equipment for forwarding call records thereto for billing. The concentrator is connected to teletypewriters and also to a storage unit for storage of call records in the event of failure of the automatic message accounting equipment.
Abstract: A distributing frame having a terminal block member attached to it by a mounting bracket which is secured either to the block member or a frame member by one of two interconnected mounting parts lying in different planes. Loosening of screw securing means passing through one of the mounting parts allows for relative movement of the mounting bracket and the respective member to reposition the securing means in the other mounting parts. This causes change in the angle of orientation of the bracket and respective member and thus causes the block member to pivot on the frame member. To connect electrical wiring to terminals on each side of the block member, it may thus be mounted in one of two alternative positions without removal from the frame while using a simple, one-piece bracket.
Abstract: A pushbutton array, connector block and a connector, for mounting in a telephone set base, are mounted on and interconnected by a flexible printed circuit member, by connection pins on each item passing through the circuit member and wave soldered. The flexible circuit member can be bent or folded so that the various items attached can be mounted in the desired relative positions and orientation.
Abstract: An electrical surge arrester module having a back-up external spark gap in its base assembly comprising an insulator plate perforated at points intermediate a terminal contact surface in said base assembly and a conductive plate at ground potential when said surge arrester module is in use.
Abstract: Apparatus is disclosed for automatically measuring accurately and rapidly alternating and direct voltages, resistance, and capacitance of a telephone line. Direct voltages and relatively high resistances can be determined by filtering out 60 Hz a.c. signals and measuring line current with and without a voltage source connected in series with the line. Capacitance is measured by charging the line from the voltage source, discharging the line into a plurality of integrators having different time constants, and sampling the output voltage of one of the integrators after a respective integral number of 60 Hz periods. The integrator whose output voltage is sampled depends on the capacitance being measured. The resultant measurement is corrected in respect of voltages on the line by performing a second integration without again charging the line, and the corrected result is modified to take into account the previously measured resistance of the line.
January 8, 1980
Date of Patent:
March 16, 1982
Northern Telecom, Inc.
Darryl C. Morris, Normand A. Saucier, Lot Phillips
Abstract: A modular switch, which can be used in telecommunications systems, provides an enclosed environment and, from a particular selection of spring cantilever contact members, a normally made, a normally open and transfer function can be provided. By shaping the body of the switch a plurality of switches can be attached together.
Abstract: Offset voltages of a precision rectifier circuit, buffer amplifiers, and an input comparator of a log converter are compensated for by charging a coupling capacitor to the combined total offset voltage of the apparatus. The charging is effected by causing the comparator to operate as a unity gain inverting amplifier during part of the operating cycle of the log converter when the comparator output signal is not used, so that the log converter operation is not adversely affected. During such charging the input of the precision rectifier circuit, to which the a.c. input signal is normally applied, is grounded. Throughout the charging and associated switching operations a capacitor of a smoothing filter connected following the precision rectifier circuit is disconnected from ground to isolate the smoothing filter output from ground and to prevent switching transients from affecting the charge of this capacitor.