Abstract: A system for testing the electrical components of vehicles during manufacturing includes a hand held tester to which a translator unit can be detachably engaged and with which the tester is in RF communication. The translator unit can be detached from the tester and plugged into a test receptacle under a vehicle's dashboard to communicate with the vehicle by translating computer formatted data from the tester to vehicle bus-formatted data, and vice-versa. Then, the vehicle's VIN is scanned into the tester or manually input into the tester, and the tester transmits the VIN via an RF link in the assembly plant to a computer in the plant. Based on the VIN, the computer determines the electric equipment that the vehicle has, and the computer transmits this information back to the tester. The tester then determines which tests to execute, and the tester causes the translator unit to undertake these tests.

Abstract: A charged voltage between the ground and a positive pole of backup capacitor 5 and a ground-casing voltage developed between the ground and a casing of capacitor 5 are determined. When the ground-casing voltage is smaller than a first value, it is judged that capacitor 5 has an opened circuit on its positive pole side; when the ground-casing voltage is larger than a second value, it is judged that capacitor 5 has an opened circuit on its negative pole side. A difference between the ground-casing voltage and the charged voltage is divided by the ground casing voltage so that a coefficient is obtained. When the coefficient is outside a predetermined range of values, it is judged that capacitor 5 is poor in capacitance, which makes it possible to determine, even in operation, whether capacitor 5 functions properly.

Abstract: A door panel is actuated when an actuator sensor disposed near the door panel senses an object approaching the door panel. When a safety sensor mounted on the door panel senses an object while the door panel is opening, the door panel is stopped. When a safety sensor mounted on the door panel senses an object while the door panel is closing, the door panel is opened. Each of the sensors includes a light-emitting unit, a light-receiving unit and a control unit, and the sensor can detect for itself failure in any of the light-emitting unit, the light-receiving unit and the control unit.

Abstract: A unique combination of nonvolatile memory (16) with a visual indicator (18) to give a device an address display which adds very little cost or space to the device and its housing. A nonvolatile RAM incorporated into the device electronics is provided with a memory location sufficient for storing the identifier in binary form. A simple visual display in the form of an LED (18) is also provided in the device housing and electrically connected to the RAM for providing visual indication of the stored number according to a predefined code.

Abstract: An arrangement is provided to power and initiate the output of information sensed and/or stored by a device in a sealed environment having a viewing window. The device is powered and the output is initiated by the input of a light source to the device. When the output is initiated, the device provides a display representing the information. In a specific arrangement, the device scrolls to display the information on a sequential, repetitive basis while the light source is directed onto the device. In one specific embodiment, the device is powered by a solar cell or the like. In one specific application of the invention, the information represents the real-time primary voltage of components and circuitry within the switchgear. In another specific application of the invention, the device is located within a sealed switchgear enclosure and the information represents the faulted phase or phases of the power distribution circuit to which the switchgear is connected.

Abstract: A sensor system includes a single sensor means, two sensed signal processing circuits for processing the output signal of the sensor means, both the signal processing circuits being substantially equal in circuit construction, and an abnormality detecting circuit for detecting an abnormality on the basis of the difference between the output signals of the two sensed signal processing circuits.

Abstract: A temperature transmitter in a process control system includes a temperature sensor which senses temperature and provides a sensor output related to sensed temperature. An analog-to-digital converter coupled to the sensor output provides a digitized output related to the sensor output. A microprocessor receives the digitized output, compensates the digitized output and provides a temperature output. Comparison circuitry compares the sensor output to a first threshold and provides an inhibit signal to the microprocessor if the sensor is outside of the first threshold.

Abstract: A harness for testing a throttle position sensor having wires operatively connected therein terminating in a connector. The harness comprises a card and a first cable of multiple wires hard-wired to the card at one end and terminating in a connector at the other. The connector of the first cable is removably connectable to the throttle position sensor connector. The card further comprises a second cable of multiple wires hard-wired to the card at one end and operably attached to a connector at another end. The connector of the second cable is a mate for the connector of the first cable. At least two terminals are mounted on the card and connected between the wires of the first and second cables for connecting the card to a digital volt/ohm meter. A light is mounted on the card and connected between wires of the first and second cables to determine and visually indicate the continuity of the throttle position sensor wires. In another preferred embodiment, the first cable comprises a plurality of other ends.

Abstract: A method of and an apparatus for communicating with the operator that of an image forming device which reduces the probability of error in acquiring a replacement consumable and which alerts the operator as to the proper disposal of the exhausted consumable. The invention utilizes status sensors within the printing device to sense when a particular consumable is exhausted or nearing exhaustion. The printing device automatically prints a hard copy page for the operator informing the user of the status of the particular consumable and corrective action to be taken. This is accomplished by a firmware implementation within the image forming device where in addition to, or in lieu of, a traditional low level status light indicator, the low level sensor sets a flag within the firmware program of the printing device which causes one or more pages of information to be printed from the image forming device.

Abstract: An electronic component failure indicator for clearly visably indicating on the surface of an electronic component to be tested a self sustaining indication of the functional operational status of the component. It is used for easily locating and identifying the exact used electronic component that has failed while it is still in a circuit and also later after it is removed from a circuit without the need of test equipment and electrical power. It includes an electronic testing circuit which continually monitors one or more parameters of the electronic component other than temperature. Upon a determination that one or more parameters has deviated from a normal condition, the test circuit generates an appropriate signal. This in turn causes a visable change in an indicator that is visable on the surface of the electronic component being monitored. In some embodiments, this may constitute a color change of the indicator, and in other embodiments, it may cause a bending or movement of the indicator.

Abstract: A system for use with aircraft having a collision avoidance system which employs i) two transponder systems each including two antennas and a selected one of two transponders and ii) a failure warning when a transponder system failure occurs, to permit the aircraft to take off when the failure warning is the result of only one antenna failure.

Abstract: A system to monitor the temperature of an integrated circuit and to dissipate heat generated thereby includes a heat sink to overlie the integrated circuit. A temperature sensor is located on the heat sink to detect the temperature adjacent the integrated circuit. Temperature signal conditioning circuitry is responsive to the temperature sensor and generates a temperature alarm signal when the temperature at the integrated circuit reaches a threshold level. A fan overlies the heat sink and draws air across and then away from the heat sink to cool it. A pressure transducer is mounted on the fan and detects air flow through the fan. Pressure signal conditioning circuitry is responsive to the pressure transducer and generates a pressure alarm signal when the air flow through the fan falls below a threshold level. Alarms are triggered by the temperature and pressure alarm signals to warn a user.

Abstract: An electrical test device for use by an electrician in testing circuits. The device includes a voltage sensor, display, and steady current source. The voltage sensor monitors the type of voltage (AC or DC) between the two conductors, and provides a signal to the display which responsively displays the type of voltage and the voltage level. The power supply has a steady current source that is in series with a tactile transducer, so that the test device may measure a broad range of voltages while only a limited amount of current flows through the voltage sensor. Consequently, lower cost components may be used in the voltage sensor. In another embodiment, the tester also includes a substantially independent continuity tester. The continuity tester includes its own power supply and alarm to indicate the continuity of a conductor and, thus, may operate even if the voltage sensor and display become inoperable.

Abstract: A portable terminal unit is connected to a network, such as a LAN, to communicate with a host apparatus. The terminal unit has a decision unit for determining whether or not the terminal unit is connected to the transmission line and/or a decision unit for determining whether or not the terminal unit is connected to the external power source. the terminal unit also has a communication controller for starting to communicate with the host apparatus when the decision units determine that the terminal unit is connected to the transmission line and/or to the external power source. The terminal unit therefor does not perform useless communication control, such as when the terminal unit is not connected to a transmission line of the LAN or to an external power source.

Abstract: A circuit arrangement includes a wear detector which is proportioned or which operates so that it wears (i.e., fails) faster than the other parts of the circuit arrangement. The wear detector may be made to wear faster than other parts of the circuit by being more heavily loaded during operation, by being configured to be more heavily stressed during operation, or by being subjected to more severe operating conditions. An indicator is connected to the wear detector so that, when the wear detector ceases to function, the indicator signals that the circuit arrangement is near the end of its useful life and is to be replaced.

Abstract: A fire monitoring system for waste bunkers includes a pair of infrared cameras, which are arranged on an axis of rotation. The axis of rotation is connected to a controllable drive motor and to an angle transmitter. Furthermore, the fire monitoring system has a computer for digitizing the thermal images determined by the pair of infrared cameras and for calculating the spatial coordinates of hot places inside the waste bunker. The calculation of these hot places is carried out based on the thermal images determined by the pair of infrared cameras and digitized, and the data supplied by the angle transmitter.

Abstract: A live insertion and removal mechanism assures that a sub-assembly being inserted or removed from a live electronic assembly does not disrupt system power and buses and is protected against the negative effects of current surge. An active current control device and related circuitry, and a connector having a plurality of graduated pin lengths effect a controlled ramp-up and ramp-down of power to the sub-assembly inserted into and removed from the live electronic assembly. Additionally, disconnecting selected output drivers from signal and control paths to avoid damage to the drivers upon insertion or removal of the sub-assembly from the live assembly.

Abstract: The system includes (1) a sensor for detecting a separation of the portable computer from an object, the sensor transitioning from an inactivated state to an activated state when the portable computer is separated and (2) an alarm circuit coupled to the sensor and having a disarmed state and an armed state, the alarm circuit detecting when the sensor is in the activated state and issuing a notification when the alarm circuit is in the armed state and the sensor is in the activated state.

Abstract: Junction overheating in an actuator controller IC used to position read/write heads in a magnetic disc storage device is prevented by temporarily decreasing actuator controller IC output signal duty cycle when excessive junction temperature is present. The present invention includes means for monitoring and comparing actuator controller IC junction temperature to a reference temperature, and for outputting a warning signal when junction temperature exceeds the reference temperature by too large a margin. The present invention introduces a time delay into the output signal from the actuator controller IC when the warning signal is present. The time delay may be fixed or variable in duration, and may be varied progressively in duration. The time delay may be generated using circuitry, software, firmware, or a combination thereof.

Abstract: A device for detecting attempts at fraud by connection of an electric feed line (13) to an apparatus for reading and writing on a chip card (3) essentially comprises a resonance unit (6) coupled to a contacting element (2) of the apparatus, and a measuring device (7). In the resonance unit (6) a generator (4) which is coupled to a resonator (1) by way of an impedance converter (5) generates a standing wave. The feed line (13) disturbs the properties of the resonator (1), that being detected by the measuring device (7) and evaluated.

Abstract: An apparatus for tripping a system for the protection of occupants of a vehicle has a first sensor (10) for sensing the acceleration of the vehicle in its direction of forward motion and a second sensor (12) for sensing the acceleration of the vehicle in a direction transverse to its direction of forward motion. The two sensors are under the control of control devices (14,16) which trigger the occupant protection system in dependence upon the signals from the first and second sensors (10,12).

Abstract: A test system is provided for the dynamic testing at the same time of a plurality of packaged charge coupled device (CCD) image sensors in which the plurality of image sensors of the same sensor type can be tested under conditions including selectable signal levels of bias control signals and selected signal levels and pulse durations of clocked control signals appropriate to the type of CCD image sensor of the plurality of sensors under test. The test system provides selectably level-adjusted control signals, selector switch means for generating selectable clock signals having the level-adjusted signal levels, and a clock driver for amplifying the clocked control signals. The amplified control signals are directed to a common input terminal of an isolation network assembly, each of separate output terminals thereof connected to a corresponding input terminal of each one of the CCD image sensors to be tested.

Abstract: A system is disclosed for monitoring the operation of an encoder having a scale which is illuminated from a light source, in which light from the scale is detected by a detector, with the encoder having means coupled to the detector for detecting in-phase and quadrature signals representing scale position, means for detecting the phase difference between the in-phase and quadrature signals, and means responsive to the detected phase difference for adjusting the output of the light source to maintain its output at a predetermined level and for providing an error signal representing the amount of adjustment of the output of the light source.

Abstract: An arrangement for detecting overheating of a power integrated circuit includes a power device integrated in a semiconductor substrate and an overheating detection circuit. The overheating detection circuit includes a reverse biased pn junction formed in the same semiconductor substrate as the power device and having a reverse leakage current flow which is temperature dependent, and a voltage converter formed in the same semiconductor substrate as the power device and coupled to the pn junction for producing a voltage depending on the reverse leakage current flow. A threshold circuit is connected for receiving the voltage and producing a signal when the voltage exceeds a threshold voltage to indicate that the power device is overheated.

Abstract: An alarm device is provided with a temperature sensor for detecting an internal temperature of a magneto-optical disc drive unit having a cooling fan and a replaceable dust filter. When the internal temperature becomes higher than or equal to a predetermined temperature due to the breakdown of the fan or the silting of the filter, the alarm device indicates an abnormal condition of the drive unit by flashing an operation indicating lamp.

Abstract: An arrangement for detecting overheating of a power integrated circuit includes a power device integrated in a semiconductor substrate and an overheating detection circuit. The overheating detection circuit includes a reverse biased pn junction formed in the same semiconductor substrate as the power device and having a reverse leakage current flow which is temperature dependent, and a voltage convertor formed in the same semiconductor substrate as the power device and coupled to the pn junction for producing a voltage depending on the reverse leakage current flow. A threshold circuit is connected for receiving the voltage and producing a signal when the voltage exceeds a threshold voltage to indicate that the power device is overheated.

Abstract: An information processing apparatus which has an apparatus main body having an operation panel and a display. A main control unit is detachably attached as a board into the apparatus main body and controls the whole apparatus such as a copying apparatus, a facsimile apparatus, or printer. A detecting circuit is provided for the apparatus main body and detects a connecting state of the operation panel of the apparatus main body and the main control unit. When the operation panel is not connected to the main control unit, the apparatus displays an error message by the display. The detecting circuit detects the connecting state by checking whether the operation panel has received an initialization command from the main control unit within a predetermined time after the turn-on of the power source or not.

Abstract: A right-angle surface-mounted light-emitting diode is mounted on a printed circuit board within a thin form factor computer cartridge. The LED is mounted, inside the cartridge assembly, close to, and facing toward, the opaque edge of the cartridge. The edge of the cartridge frame has a small diameter hole, through which a clear light-transmitting material is installed. This light-transmitting material forms a light pipe which conducts the light emanating from the LED out of the card.

Abstract: A tamper detection system for promptly warns a utility that it has lost control of a load which is part of a load management system, and may be giving price incentives to a customer without receiving the corresponding benefit arising from the intended control of the load. A monitor circuit automatically determines whether the load management device is connected to the load by detecting whether a current is passing via the load control device to the load, and generates a warning signal when no current is detected for a first predetermined period of time. The load current is detected either by inductively coupling a conductor to the load with a sensing conductor, or by sensing current induced in the load control relay as the load current passes through the relay contacts. The tamper detection feature operates without any activity of the load management device, and detects disconnection of the load even when the load management device itself is powered up and working properly.

Abstract: An apparatus for contactless data and energy transmission and includes a stationary part having device for transmitting and receiving data and device for generating energy. A movable part has a plurality of rectifier devices each with at least one output and modulators each being connected downstream of a respective one of the rectifier devices. A first pair of coils is connected to the device for transmitting and receiving data and to the rectifier device for transmitting data from the stationary part to the movable part. A second pair of coils is connected to the device for generating energy and to the rectifier device for transmitting energy from the stationary part to the movable part. The coils in the stationary part are arbitrarily associated with the coils in the movable part, and data is transmitted from the movable part to the stationary part by a load variation at the coil of the movable part not being used for energy transmission.

Abstract: A surge arrester 2 comprises eight surge arresting varistor blocks 4 stacked within a polymeric outer insulating housing 14. A fibre optic cable 16 is fed into the surge arrester 2 through one end electrode 6, helically wound around all the blocks 4 in good thermal contact therewith and exits through the same electrode 6. A monitoring arrangement 18 compares the light incident on and emergent from the optical cable 16 to determine its integrity and thus the integrity of the surge arrester 2.

Abstract: In accordance with the invention there is provided a test device for testing a circuit including a compact fluorescent light having first and second terminals, an ac-power source including first and second ac-power lines, and a ballast in the ac-power source. The test device has current indicating means for testing presence of electric current in the circuit, and voltage indicating means for indicating presence of voltage between the first and second power lines.

Abstract: A drive current for driving actuators is generated based on a first digital signal comprising n-bit binary data which is supplied from a microprocessor and it is applied to an excitation coil. The drive current is supplied to the exciting coil and is converted into a voltage which is then converted into a second digital signal comprising n-bit binary data. The binary data of the second digital signal is compared with the digital data of the first digital signal to detect an alarm condition. Furthermore, the second digital signal is compared with first and second reference value to set plural alarm conditions.

Abstract: A system is provided for monitoring signals from a linear or rotary encoder or scale to provide a warning of a malfunction of the encoder or to be able to predict a future malfunction. The system includes a feedback circuit for comparing the output of the detector in the encoder with a voltage reference and for either raising or lowering the voltage to the light source for maintaining constant maximum detected light amplitude regardless of dirt build-up on the scale with the amount of voltage correction to the light source being an indicator of the level of functioning of the encoder. The system also assures constant amplitude output signals from reflectance-type encoders in which the light source and detector are on the same side of the scale and in which the subject servo system maintains a constant amplitude reflected beam.

Abstract: A tester is provided for a control yoke of an oil-filled electrical power switch. The tester can be easily and safely used by a line crew member. The tester is connected to the yoke which carries electrical signals to control the position of the switch. Control signals are then furnished to the yoke in the usual manner. Indicators on the tester identify whether the yoke or the switch is the source of the problem.

Abstract: A single hand-held tester performs both off-line continuity tests and on-line voltage tests for electrical cables and equipment such as that used in entertainment, studio or stage lighting. A test plug and a test socket fixed one at each end enable the tester to (a) plug into a power outlet socket to check for the correct presence of a.c. line voltage, (b) engage both ends of an extension cable to test continuity and correct wiring of each wire in the cable or (c) engage the plug end of an extension cable to provide audible indication of the continuity of a load such as a lamp connected to the cable. In a three-conductor (hot, ground and neutral) embodiment, a row of three test pushbuttons, one for each conductor, corresponds with an adjacent row of three LED continuity indicators. Three neon lamps indicate the presence of a.c. voltage between contact members of a power outlet under test.

Abstract: There is provided a method for diagnosing an abnormal state of a sensor having a nonlinear output characteristic in which an output signal of a sensor changes nonlinearly. The method includes the steps of determining a first detection value which is indicated by the output signal of the sensor at a predetermined time, and determining a second detection value which is indicated by the output signal of the sensor obtained when a detection value indicated by the output signal has changed by a predetermined variation from the first detection value. The method also includes judging whether or not a deviation between the first detection value and the second detection value is out of a predetermined range, and determining that the sensor has an abnormal state when it is determined that the deviation is out of the predetermined range.

Abstract: An electrical connector with visual display connecting an information bus to a computer in an information processing system including electronics mounted within a connector body and coupled to the information bus, the electronics monitoring information flowing through the information bus and providing output signals in response thereto and visual display circuitry mounted in the connector body and connected to receive the output signals from the electronics and provide a visual display in response thereto indicating the flow of information through the bus.

Abstract: In a triac power switching system, two triacs are connected in series between an AC power source and a load. Each time power is applied to a load, the triacs are tested by first turning on one of the triacs while maintaining the other triac turned off, then turning on both triacs to apply power to the load for a set time interval and then turning off one of the triacs and determining whether power is still applied to the load. If power is applied to the load while either one of the triacs is supposed to be off, an alarm is sounded. In addition, if power is not applied to the load when both triacs are turned on, an alarm is sounded.

Abstract: The planarity of semiconductor device pins is measured simultaneously by multiple pneumatic comparator circuits by detecting pressure changes proportional to pin position.

Abstract: There are disclosed a system for and a method of detecting a reverse packaging of a PROM capable of judging the packaging state of PROM having different impedances by adding an impedance switching circuit to the conventional socket. The method includes the steps of turning off the switch in the impedance switching circuit so that the socket receives a first voltage supplied from one of the impedances, storing the first voltage received by the socket, turning on the switch in the impedance switching circuit so that the socket receives a second voltage supplied from another impedance, storing the second voltage received by the socket, and judging that the PROM is normally packaged in the socket in case that the first voltage is equal to the second voltage and the PROM is reversely packaged in the socket in case that the first voltage is not equal to the second voltage.

Abstract: Temperature sensors are located inside drive chambers where disk drives are located to signal an overheating condition. An overheating condition triggers external alarms and produces an interrupt signal to the disk drive controller, which, in turn, alerts the operating system. If the operating system does not comprehend the problem and take the appropriate action, the controller shuts down the disk drives after a certain period of time.

Abstract: A circuit for testing a liquid crystal display for open data lines, for identifying select lines shorted to data lines, and for identifying failed data line scanner stages includes thin film transistors arranged between each data line and a segmented bus. A sectioned shift register sequentially actuates the thin film transistors and the bus segments are monitored while data signals are applied to the data lines. The absence of a voltage on the bus indicates an open data line. The bus is also monitored while select signals are applied to the select lines and the shift register sequentially actuates the thin film transistors, the presence of a voltage on the bus indicates a short between a data line and a select line.

Abstract: A method and apparatus for analyzing a semiconductor device having a diode formed therein. In its broadest sense, the invention involves irradiating the semiconductor device with electromagnetic radiation while monitoring the leakage current output from the diode contained in the semiconductor device. If the semiconductor device is present and properly soldered to the printed circuit board, an increase in the leakage current will be observed during the irradiation process. The increase in leakage current is also representative of the presence of intact bond wires at both the pin under test and the ground pin. The invention in a preferred form is shown to include a voltage source, electrically connected to the diode, for biasing the diode in a reverse direction, a current monitor, connected to monitor the leakage current from the diode and an electromagnetic radiation generator, positioned to provide electromagnetic radiation incident on the semiconductor device.

Abstract: Disclosed is a system for determining whether semiconductor components are present and properly connected to a printed circuit board. The semi-conductor material between two pins of an integrated circuit forms a lateral NPN transistor, having its base connected directly to the substrate connection pin of the component. A constant voltage source is applied to the lateral transistor collector pin of the component being tested, and allowed to stabilize. A current or voltage source is then connected to the emitter pin of the lateral transistor, typically an adjacent pin, and a current or voltage pulse is applied to this pin. The current on the collector pin is then monitored and if a corresponding current pulse is detected, the emitter and collector pins, as well as the substrate connection pin of the component, are properly connected to the printed circuit board.

Abstract: An overheating detection circuit has a simple circuit construction and may be formed in the same substrate as that of a power integrated circuit. It can produce a large output signal in response to detection of a temperature within a preselected range of detection temperatures. The circuit includes a reversely biased junction having a temperature dependent reverse leakage current, means for amplifying the reverse leakage current, and means for producing a voltage in accordance with the amplified reverse leakage current and for producing a signal when the voltage exceeds a threshold voltage to indicate that the power integrated circuit is overheated.

Abstract: A safety device for vehicle occupants has an operational voltage source, typically the vehicle's battery, and a storage device for electrical energy, typically a capacitor. Several tripping devices, typically ignition tablets, are coupled to the storage device and/or the operational voltage source, for actuating inertial restraining devices, such as airbags, belt tighteners or the like. If the storage device fails, each tripping device is connected for a specified period of time to the operational voltage source by a respective switch. Each switch is triggered by an evaluating device. Therefore, if the storage device fails, as long as the operational voltage source is connected to the safety device, each tripping device and, therefore, inertial restraining device can be actuated.

Abstract: An electronic motor control system is taught herein which utilizes a speedometer testing circuit. The (electronic) speedometer/odometer of a vehicle is tested, with the testing device being interconnected with the (input) terminals of the speedometer, exclusive of whether the speedometer is installed or removed from the vehicle. The testing device is utilized without vehicle input to the speedometer in order to determine whether the speedometer can produce an expected signal upon testing thus determining whether the speedometer is functional or not. The testing circuit has a self-contained power supply, is compact in size, and lightweight, thereby insuring complete mobility of the testing unit and dual application of the circuit to both installed and disengaged speedometer and odometer mechanisms.

Abstract: In the copy prevention apparatus and its method, it is discriminated whether an object is legally copied or not; a constant event is generated at or below a predetermined probability; and an abnormal operation is executed only if the two conditions of the object having been determined as an illegal copy, and the event having been generated, are satisfied. Therefore, even if the object is determined as an illegal copy, the abnormal operation is not always executed, but executed at or below a predetermined probability. Although the occurrence of the abnormal operation can be indicated to the user immediately, it is also preferable to keep the abnormal operation occurrence secret for a time and inform the user of the occurrence an appropriate time later.

Abstract: In a system for controlling a vehicle by exchanging signals between an electronic controller for controlling a vehicle transmission and another electronic controller for controlling a vehicle engine, the transmission controller incorporates a monitor circuit which receives, via an interface circuit of the engine controller, a signal output from the transmission controller through a communication circuit, and which is capable of detecting abnormalities of the interface circuit of the engine controller. If an abnormality of the interface circuit of the engine controller takes place such that the engine torque cannot be reduced although the transmission controller issues an instruction to reduce the engine torque, the transmission controller maintains the line pressure instead of reducing the same to cope with such a situation, thus effecting fail-safe control.