Cable Or Capacity Patents (Class 178/63R)
  • Patent number: 5120909
    Abstract: A circuit for detecting and verifying a presence of a terminating device for a high speed data transmission line. The circuit contains a first cable detector which generates a first signal if a first cable is present. A second cable detector generates a second signal if a second cable is present. The terminating device is contained in a plurality of resistor packs, each of the which contains an extra resistor. A terminating device detector senses the extra resistor presence, thereby detecting the presence of the resistor packs. The terminating device detector generates an ALL-EQUIPPED signal and a NON-EQUIPPED signal, the ALL-EQUIPPED signal is generated when all of the plurality of resistor packs are present, the NON-EQUIPPED signal is generated when all of the plurality of resistor packs are absent. Finally, a verifier circuit receives the first signal, the second signal, the ALL-EQUIPPED signal and the NON-EQUIPPED signal.
    Type: Grant
    Filed: April 26, 1991
    Date of Patent: June 9, 1992
    Assignee: AG Communication Systems Corporation
    Inventors: David A. Kutz, Tod R. Earhart
  • Patent number: 5073920
    Abstract: A subscriber line measuring method and apparatus can charge a line capacitance of a telephone subscriber line in a very short time as compared with a prior art by charging the line capacitance by a predetermined current without use of a high resistor (100 k.OMEGA.) in a conventional measuring apparatus, and thereby can measure an impedance of the telephone subscriber line in a very short time with high accuracy.
    Type: Grant
    Filed: August 17, 1990
    Date of Patent: December 17, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Hirohumi Masukawa, Makoto Hisamura
  • Patent number: 4995054
    Abstract: A transmission arrangement includes a switched resonant circuit (5) for switching data states of digital signals on a pair of transmission lines (1, 2) and a regenerative circuit (7) for feeding power back on the lines. The switched resonant circuit has a switching device (22) connected in series with an inductance (20) and parallel with a capacitance (21). A digital logic system (8) controls the switching device such that switching occurs at a line current zero crossover point. Where a change of data state is to be transmitted to a receiver (6), the logic system (8) turns the switching device on at an appropriate time. The switching device is switched off when the voltage (+Vm) on the lines reaches approximately the same magnitude in the opposite sense (-Vm). The change in the line voltage indicates a change of the data state to the receiver.
    Type: Grant
    Filed: April 14, 1989
    Date of Patent: February 19, 1991
    Inventor: Gregory P. Eckersley
  • Patent number: 4736385
    Abstract: High frequency transmitter and receiver circuits are AC coupled for party line transmission over coaxial cable where the circuits are connectable to the cable by use of stinger taps and thereby eliminate the need to interrupt service when connecting the circuits to the cable. The transmitter circuit includes oppositely polled current sources which are alternately switched to the coaxial cable via the stinger tap or to a dummy load by current switches connected to data inputs via buffer circuits. A transmit enable circuit controls the current sources to be active or inactive and to prevent unbalances from saturating either current sources. The receiver includes a high input impedance biasing network and buffer amplifier that maintain the high input impedance even when power is off. Capacitance at the tap is reduced by a capacitor drive circuit which feeds input signal back to transmitter blocking diodes and to the trunk tap.
    Type: Grant
    Filed: January 27, 1987
    Date of Patent: April 5, 1988
    Assignee: Computer Network Technology Corporation
    Inventors: Warren R. Pratt, Charles R. Rogers, Dennis G. Cope
  • Patent number: 4734919
    Abstract: A circuit for serial data communication and power transmission between a main controller and a sub-station along two balanced transmission lines. The circuit includes a power supply for providing a DC voltage to the sub-station along the transmission lines. A main controller sending circuit generates two data signals of substantially equal magnitude and opposite polarity and supplies the data signals to the transmission lines. A sub-station receiving circuit detects the data signals, on the transmission lines and converts the data signals into a serial format output data signal.
    Type: Grant
    Filed: February 12, 1982
    Date of Patent: March 29, 1988
    Assignee: Gold Star Tele-Electric Co., Ltd. Incorporated
    Inventor: Choe J. Tae
  • Patent number: 4592033
    Abstract: The data transmission rate in a cable telemetry system is improved by preconditioning an encoded data signal prior to discriminating and decoding it with a filter/amplifier employing an operational amplifier having a non-inverting input connected to receive the data signal, an inverting input which is grounded through a series connected resistance and capacitance and an output which is feedback connected to said inverting input by a resistance.
    Type: Grant
    Filed: May 2, 1983
    Date of Patent: May 27, 1986
    Assignee: Mobil Oil Corporation
    Inventor: Charles L. Dennis
  • Patent number: 4520488
    Abstract: A communication system for communicating analog and digital data with a process variable, e.g., pressure, transmitter over the two wires which supply power to the transmitter apparatus. The digital communication operation is half-duplex, bit serial transmission and is represented by the currents and voltages in the transmitter communication loop which are selectively introduced between process variable analog data transmissions of 4-20 ma. A plurality of bit cells are provided for each data word or byte between a start bit and a parity bit cell. Following the completion of transmission of the digital data, a predetermined time period is introduced to enable the resumption of transmission of process variable data. Multiple byte digital data transmission can also be effected between process variable analog transmissions by having a byte spacing less than the predetermined time period preceeding the 4-20 ma process variable transmissions.
    Type: Grant
    Filed: November 2, 1981
    Date of Patent: May 28, 1985
    Assignee: Honeywell, Inc.
    Inventors: Felix J. Houvig, Ronald H. Rowlands
  • Patent number: 4434497
    Abstract: Bidirectional circuitry, which includes two amplifiers, each having a capacitor connected between an input and an output terminal thereof, and two interrupt transistors, acts to provide amplification and/or level shifting of information between two transceivers while also reducing capacitive loading and thus enhancing response time.
    Type: Grant
    Filed: December 22, 1981
    Date of Patent: February 28, 1984
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventor: Robert M. Rolfe
  • Patent number: 4425663
    Abstract: A data communications transceiver for transmitting signals to and from a medium has an output driver connected to the medium through a series connected first pair of diodes and a receiving transistor amplifier whose input is connected to the medium and whose output leads are each connected to a separate one of a second pair of diodes, whereby a low input capacitance is achieved.
    Type: Grant
    Filed: February 20, 1981
    Date of Patent: January 10, 1984
    Assignee: TCL, Inc.
    Inventor: Tat C. Lam
  • Patent number: 4403111
    Abstract: An interface for connecting data terminal equipment (DTE) to data communication equipment (DCE) is provided which requires no modification to an existing and widely accepted DCE connector and yet which permits data communication according to more recently adopted functional interface standards through the same DCE connector. Specifically, in a single 25-position interconnection configuration for DTE, an interface is provided which supports (1) the EIA Standard RS-232C interface with unbalanced generators and receivers at generally established RS-232C pin assignments at a DCE terminal junction; (2) an RS-449-type interface with balanced generators and receivers with pin assignments at locations incapable of being confused with RS-232C interface connections at a DCE terminal junction; and (3) an RS-449-like interface with balanced generators and receivers in a variety of multiple-point applications.
    Type: Grant
    Filed: July 15, 1981
    Date of Patent: September 6, 1983
    Assignee: ICOT Corporation
    Inventor: Bruce Kelly
  • Patent number: 4385394
    Abstract: A system for transmitting and receiving serial data over a pair of differential lines so that relatively large differences in ground potential will not affect the integrity of the transmitted data. Each differential line has a first switch for pulling the line high and a second switch for pulling the line low. Logical gates hold all switches off to allow the lines to float in response to a first control signal. A second control signal enables the logical gates to pull the first differential line up and the second differential line down whenever true data is to be sent and for pulling the second differential line up and the first differential line down whenever data is true. Associated with each switch is a protective diode and cold filament lamp for protecting the respective switch and insuring system operation even if large swings in ground potential occur.
    Type: Grant
    Filed: January 23, 1981
    Date of Patent: May 24, 1983
    Assignee: Datavision, Inc.
    Inventor: Roger D. Pace
  • Patent number: 4341927
    Abstract: Signal data is generated by interconnected non-inverting and inverting voltage followers and is transmitted on power-carrying conductors to a remote detection circuit comprising a differential amplifier which receives equal in-phase signal inputs of opposite polarity, thereby effecting cancellation of any externally-induced noise which might accompany the signal data.
    Type: Grant
    Filed: August 11, 1980
    Date of Patent: July 27, 1982
    Assignees: TIE/Communications, Inc., Nippon Tsushin Kogyo K.K.
    Inventors: Tsuyoshi Shinoi, Fumikazu Hamatani
  • Patent number: 4322854
    Abstract: A data communications terminal is provided for interfacing with a central data processing system to handle a variety of data acquisition and control functions including the minitoring and control of security devices and pay television receivers. The terminal includes a microcomputer unit for receiving and processing data from the central processing system and from remote units which generate data signals in response to abnormal conditions. A data reception and transmission unit include a radio frequency modem for converting data to and from a frequency modulated format and a data converter for changing the serial bit data to parallel word data. An identification unit provides data to the microcomputer regarding the identification of the terminal which can be compared to the address portion of the incoming data from the central processing system. Data generating means are provided for generating and transmitting response data to the microcomputer for transmission to the central processing system.
    Type: Grant
    Filed: May 18, 1979
    Date of Patent: March 30, 1982
    Assignees: Allan B. Bundens, Carl F. Schoeneberger
    Inventors: Allan B. Bundens, Carl F. Schoeneberger
  • Patent number: 4184045
    Abstract: Serial transmission of binary information on a two-conductor line is effected by transmitting a periodic signal on one conductor and earthing the other conductor when a binary "0" is to be transmitted, while the periodic signal is transmitted on the other conductor and the first conductor is earthed when a binary "1" is to be transmitted. The sum of the signals transmitted via the two conductors is established for controlling the recovery of the binary information from the difference between the signals transmitted on the two conductors. On the transmitter side, use is made of a switch controlled by the binary information, for connecting the periodic signal to either of the two conductors and, on the receiver side, use is made of a correlator or a signal-adapted filter for recovering the transmitted information.
    Type: Grant
    Filed: May 25, 1978
    Date of Patent: January 15, 1980
    Inventors: Lars H. G. Philipson, Gert-Ake G. Hansson
  • Patent number: 4099022
    Abstract: A system for data pulse transmission through a single-wire, water-return cable payed out from a coil in an open pack to any selected length over a predetermined wide range (e.g., 4K to 16K feet) employing a toroidal core around the cable near the pack and a multiturn primary winding on the core. The single-wire cable constitutes a single turn secondary winding terminated at the receiver end by a resistor and coupled to the water (circuit ground) at the transmitting end by stray capacitance between the cable remaining in the pack and the surrounding water. The receiver employs an equalizing network to compensate for the amplitude-frequency characteristic of the cable of nominal length within the predetermined range resulting in only slight over-compensation for a shorter cable length and slight under-compensation for a longer cable length.
    Type: Grant
    Filed: January 5, 1977
    Date of Patent: July 4, 1978
    Assignee: Bunker Ramo Corporation
    Inventors: Robert A. Fullerton, George V. Podraza