Abstract: A circuit and a method for interpolative delay is provided. The circuit includes a delay locked loop with interpolation delay. The delay locked loop includes a differential inverter, an interpolation circuit, and a differential compare circuit. The differential inverter is coupled to receive a differential clock signal and coupled to provide an inverted differential clock signal. The interpolation circuit is coupled to receive both the clock signal and the inverted clock signal, and to provide an interpolated clock signal having a first delay relative to the clock signal. The differential compare circuit is coupled to receive the inverted clock signal and coupled to provide a non-interpolated clock signal having a second delay relative to the clock signal. The second delay corresponds to a full delay of the differential inverter and the first delay corresponds to a predetermined fraction of the full delay.

Abstract: A semiconductor integrated circuit includes a first data holding section, a first pull-up circuit, a first pull-down circuit, a first feedback circuit, and a second feedback circuit. The first data holding section holds first output data. The first pull-up circuit takes in input data as a pull-up control signal and, when the pull-up control signal takes one value, pulls up the first output data. The first pull-down circuit takes in the input data as a pull-down control signal and, when the pull-down control signal takes the other value, pulls down the first output data. The first feedback circuit feeds back a first feedback signal corresponding to the first output data as the pull-up control signal to the first pull-up circuit. The second feedback circuit feeds back a second feedback signal corresponding to the first output data as the pull-down control signal to the first pull-down circuit.

Abstract: A pseudo true single phase clock latch (pseudo “TSPC” latch) includes additional circuitry coupled to three previously floating nodes that can lose data depending upon the amount of leakage current associated with these nodes. The additional circuitry, including a positive feedback circuit, improves the performance of a true single phase clock latch circuit at lower frequencies without significant degradation in high frequency operation of the latch.

Abstract: A low-voltage constrained coefficient adaptation and multiplication is provided. To provide the constrained coefficient adaptation, an adder adds an adaptive differential control voltage to a forcing differential control voltage to provide an effective coefficient. The adder is configured such that the forcing differential control voltage can prevent the adaptive differential control voltage from producing a sign change in the effective coefficient.

Abstract: Circuitry and methodology for controlling a FET or another transistor device provided to supply power to a circuit board insertable into a live backplane to provide inrush current slew rate control. The FET control circuit is responsive to an input signal variable in a preset manner to produce a FET control signal for controlling the FET so as to form an output signal corresponding to the input signal. The control circuit is configured to prevent the uncontrollable step in the output from being produced when the FET control signal reaches a level sufficient to control the FET. In one embodiment, a comparator is provided for comparing the FET control signal with a reference value that may correspond to a current for charging a control terminal of the FET to prevent the input signal from changing until the FET control signal exceeds the reference value.

Abstract: According to the present invention, there is provided a semiconductor switching circuit having: a common terminal; first, second, and third terminals; first, second, and third ground terminals; first, second, and third control terminals; a first through FET having a source and drain connected in series between the common terminal and first terminal, and a gate connected to the first control terminal via a first resistor; a second through FET having a source and drain connected in series between the common terminal and second terminal, and a gate connected to the second control terminal via a second resistor; a third through FET having a source and drain connected in series between the common terminal and third terminal, and a gate connected to the third control terminal via a third resistor; 11th and 12th shunt FETs each having a source and drain connected in parallel between the first terminal and first ground terminal; 21st and 22nd shunt FETs each having a source and drain connected in parallel between the

Abstract: A step-down voltage output circuit preventing: latch-up phenomenon in a load circuit for a period between a power-supply activation and complete start of a charge pump circuit; and rapid change of a substrate potential when a step-down voltage output is changed from ON to OFF. The step-down voltage output circuit has a timer circuit that operates depending on control signals and a timer period; a first N-channel MOS transistor in which a source is connected to a step-down voltage output terminal, a drain is connected to ground, a gate is connected to a power-supply voltage input terminal through a resistance; and a second N-channel MOS transistor in which a source is connected to the step-down voltage output terminal, a drain is connected to the gate of the first N-channel MOS transistor, and a gate is connected to an output terminal of the timer circuit.

Abstract: A band-gap reference circuit for generation of voltages and currents independent of process, voltage, and temperature includes three inversely proportional to absolute temperature (IPTAT) current generators. The IPTAT current generators generate three currents that are added to generate a current independent of the absolute temperature. The generated current is passed through a switched capacitor resistor to generate the band-gap reference voltage across the switched capacitor resistor.

Abstract: Disclosed is a voltage regulator capable of reducing a set-up time. A driver is connected between a power supply terminal and the output terminal, and supplies a power supply voltage to the output terminal in response to a signal of a control node. A first signal generator provides a first signal to the control node when a voltage of the output terminal is lower than the target voltage. A second signal generator provides a second signal to the control node for a predetermined period of time when the voltage of the output terminal becomes higher than a detection voltage while the first signal generator is providing the first signal to the control node.

Abstract: A multi-channel current regulator includes two or more channels, each channel acting as a current source or sink for a respective load. Each channel regulates its load current so that the load current is proportional to an input voltage supplied to the channel. Each channel also generates a feedback voltage that is proportional to the load current of the channel. The current regulator also includes an operational amplifier. The amplifier is connected, using two multiplexors to drive one channel at a time. Each channel is selected in a rotating sequence for connection to the amplifier. Internal gate capacitance maintains each channel not connected to the amplifier at its previously set load current.

Abstract: Systems and methods are disclosed to adaptively pre-distort a signal prior to being used by a non-linear circuit, such as a higher power amplifier (at transmit) or a low noise amplifier (at receive). The signal is compared with a feedback signal from the non-linear circuit and a metric is calculated and minimized. The input signal is adaptively changed, such as by varying tap coefficients, until the metric is sufficiently minimized, resulting in a pre-distorted signal that is substantially linear upon passing through the non-linear circuit.

Abstract: The present invention introduces methods and circuits to amplify audio signals for driving speakers. An additional feedback circuit is added in an audio amplifier to couple the amplifier stage and output stage of the audio amplifier. The feedback circuit turned off as long as output voltages of the audio amplifier are not near saturation. The feedback circuit is turned on to reduce audible noises if output voltages of the audio amplifier are near saturation.

Abstract: A differential preamplifier includes an active load with adjustable common-mode output level. The active load includes a transistor pair, a resistor pair, and a current source. The transistor load is employed to provide high gain, low offset, and a large bandwidth for the differential preamplifier. The resistor pair and current source are used to increase the common-mode output level of the differential preamplifier and to bias the transistor load. The current source can be varied to provide an adjustable common-mode output level suitable for driving next stage devices. The active load design allows the differential preamplifier to operate using only low power voltage supplies and with small-sized transistors.

Abstract: A method for simplifying common mode feedback circuitry utilized in multi-stage operational amplifiers may comprise generating a first differential output signal by a first amplifying circuit in an amplifying stage and communicating the first differential output signal to a first output of the amplifying stage. A second amplifying circuit in the amplifying stage may generate a second differential output signal that may be communicated to a second output of the amplifying stage. The second differential output signal may be fed back to a first feedback circuit in the amplifying stage, and the first differential output signal may be fed back to a second feedback circuit in the amplifying stage. Additionally, the first and the second differential output signals may be fed back to the second feedback circuit and the first feedback circuit, respectively, in a first amplifying stage and/or any one or more of succeeding amplifying stages.

Abstract: A phase locked loop is disclosed and includes a frequency divider circuit with a settable division ratio in a feedback path. The division ratio is produced using a control circuit which, besides an input for supplying the integer and fractional components for the frequency division ratio which is to be set, includes an input for supplying a phase correction signal. To produce the phase correction signal, the phase locked loop further includes a phase correction apparatus. The phase correction signal preferably contains a signal component with an exponential profile, and is supplied to the control circuit for producing a frequency division ratio for the frequency divider circuit such that it compensates for a phase drift in the output signal from the voltage controlled oscillator in the phase locked loop.

Abstract: Electronic circuitry comprising operational circuits of active switching type requiring timing signals, and conductive means for distributing said timing signals to the operational circuits, wherein the timing signal distribution means includes a signal path that has different phases of a drive signal are supplied via active means at different positions about the signal path where that path exhibits endless electro-magnetic continuity without signal phase inversion or has interconnections with another signal path having different substantially unidirectional signal flow where there is no endless electromagnetic continuity between those signal paths and generally has non-linear associated circuit means where the signal path is of a transmission line nature.

Abstract: In an oscillation apparatus formed by a ring oscillator including an odd number of inverters (more than two inverters) connected in a ring, each of the inverters having one drive MOS transistor and one load MOS transistor, a constant voltage generating circuit is adapted to generate a constant voltage corresponding to a threshold voltage of the drive MOS transistor, and a voltage-to-current converting circuit is adapted to convert the constant voltage into load currents. Each of the load currents flows through the load MOS transistor of one of the inverters.

Abstract: There is provided a non-reciprocal circuit device which is considerably small in size and has excellent mass productivity as compared with a conventional counterpart. A gyromagnetic component 1, a permanent magnet 2 and yokes 31 and 32 are provided. The permanent magnet 2 is provided on at least one surface side of the gyromagnetic component 1, and applies a direct-current magnetic field to the gyromagnetic component 1. The yokes 31 and 32 form a magnetic path for a magnetic field generated by the permanent magnet 2. At least one side surface of the permanent magnet 2 is exposed to the outside to constitute an external wall surface.

Abstract: A controller sends signals to an electromagnetic coupler associated with a bus. The signals are arranged to set a coupling strength of the coupler.

Abstract: A connection structure is applied to mutually connect a first and a second transmission line that is planar in shape and that has a ground conductor on a second main surface, such as a microstrip line or a coplanar line with a ground. The first and the second transmission lines are superposed one upon the other, and their signal wiring patterns are electrically connected, as are their ground conductors. An end surface of the first transmission line is substantially covered by a conductor layer connected to the ground conductor. The connection structure can achieve good signal transmission characteristics up to high-frequency bands on the order of several tens of gigahertz.

Abstract: A tunable microwave device includes a SOI structure. A buffer layer is formed on the SOI structure. A microwave film layer is formed on the buffer layer. The microwave film layer comprises BST related materials.

Abstract: The present invention is to provide a harmonic spurious signal suppression filter, which comprises microstrip lines disposed on a printed circuit board of a wireless network product, wherein one end of a microstrip input end is perpendicularly connected to one end of a first microstrip line, one end of a microstrip output end is perpendicularly connected to one end of a fourth microstrip line, the first and fourth microstrip lines are interwovenly arranged in an interdigital finger form, a second microstrip line is extended from both the microstrip input and output ends, and each end of the second microstrip line corresponding to the location of the first and fourth microstrip lines is connected to a third microstrip line of a meandering shape.

Abstract: Provided is a narrowband microstrip type bandpass filter adapted- to a home network, telematics, an intelligent traffic system, and a satellite Internet, the microstrip type bandpass filter comprising: an input terminal for receiving a predetermined signal; an output terminal for outputting a selection signal in a characteristic band; a first resonator electrically coupled with at least a portion of the input terminal; a second resonator electrically coupled with at least a portion of the first resonator; and a third resonator electrically coupled with at least a portion of the output terminal and the second resonator, and a magnetic coupling is provided using a cross coupling gap or a cross coupling line between non-adjacent resonators, so that a pattern can be simplified by optimizing the design and the manufacturing process to provide low-cost millimeter-wave parts, the manufacturing cost can be reduced by miniaturizing the parts, and the mass production can be readily realized.

Abstract: The invention relates to a microwave filter comprising a coaxial structure, consisting of a tubular outer conductor and an inner bar conductor. According to the invention, the inner bar conductor extends in an axial direction inside the outer tube and, together with said tube, forms a series of concentric slots in the axial direction thereby defining successive coaxial line segments with low characteristic impedance and coaxial line segments with high characteristic impedance. The aforementioned concentric slots are produced in a synthetic foam block.

Abstract: Methods, systems, and apparatuses are disclosed for magnetically-actuated relays/switches that suppress cantilever and/or hinge deformation. A permanent magnet produces a first magnetic field. A movable element is held between a pair of axially-aligned, rotationally flexible hinges. A space is present between the permanent magnet and the movable element. The space allows at least one end portion of the movable element to move toward the permanent magnet. A bar member is positioned in the space. A coil produces a second magnetic field to switch the moveable element between first and second stable states. At least the central portion of the movable element is magnetically attracted toward the permanent magnet. The bar member physically prevents the central portion of the movable element from flexing toward the permanent magnet due to the magnetic attraction.

Abstract: A complex relay device has at least one bus bar base plate, two relay units, and a relay case. The bus bar base plate has multiple bus bars that have ends providing terminals and are formed in predetermined circuit patterns. The bus bars are integrated and covered with a resin except for at least the ends. The two relay units are fixed on the bus bar base plate such that the two relay units are adjacent to each other and are connected to the terminals, which are used for external connection, through the bus bars. The relay case accommodates the bus bar base plate and the two relay units.

Abstract: A magnetic switch and children's apparatuses, such as print media apparatuses and plush dolls, which include magnetic switches are disclosed. One magnetic switch includes a first conductor and a second conductor spaced apart from the first conductor. A third conductor is disposed under the first and second conductors, the third conductor being formed from a magnetic material. A magnet is also included, the magnet being adapted to move the third conductor towards the first and second conductors so as to form a conductive bridge. Another magnetic switch includes a first conductor and a second conductor spaced apart from the first conductor. A first magnet is disposed under the first and second conductors. A second magnet is also included, the second magnet being adapted to move the first magnet so that the first and second conductors form a conductive bridge.

Abstract: A power inductor comprises a magnetic core material having first and second ends. An inner cavity arranged in said magnetic core material extends from the first end to the second end. A conductor passes through the cavity. A slotted air gap is arranged in the magnetic core material and extends from the first end to the second end. An eddy current reducing material is arranged in the cavity. The eddy current reducing material has a permeability that is lower than said magnetic core material.

Abstract: A planar magnetic device comprising a molded header and a planar core assembly, and a method of making a planar magnetic device. The molded header has first, second, third, and fourth sides and an aperture in the center. The first side has a plurality of terminals positioned through it. The third and fourth sides have upper surfaces that are lower than the upper surfaces of the first side. The planar core assembly comprises planar windings and a core. One side of the planar winding has a plurality of terminals with through-holes so that the primary terminals of the header are positioned through the through-holes. The core surrounds at least a portion of the planar windings. The core is shaped so that a first portion of the core is positioned in the aperture, a second portion of the core is positioned on the upper surface of the third side, and a third portion of the core is positioned on the upper surface of the fourth side.

Abstract: A movable operating member 5 is swingably borne by the base 1, and its distal end is moved upward by allowing its proximal end 5b to be pressed downward. The movable contact 3 is separated from the stationary contact 2 upward by moving the distal end of the movable operating member 5 upward. The proximal end of the movable operating member 5 is pressed downward by a guide pin 6 in response to a reverse action of a bimetal 7. When a reset shaft 8 is pushed upward, the movable contact 3 is pressed upward, and the guide pin 6 is pressed upward so that the bimetal 7 can be returned to an initial state.

Abstract: A sensor system has an AlN substrate, a W layer on the substrate, a signal source adapted to apply an electrical actuating signal to the W layer, and a sensor adapted to sense the response of the W layer. The W layer can comprise a thin film, with various types of optional protective layers over the film. Applications include sensing temperature, fluid flow rates, fluid levels, pressure and chemical environments. For a planar heater, the W layer comprises a plurality of conductive strands distributed on the substrate, with the strands generally parallel and serpentine shaped for a rectangular substrate, and extending along respective lines of longitude that merge at opposite poles of the substrate for a circular substrate.

Abstract: A system and method of providing security for a vehicle starting system. The method including a first step of storing secure information identifying an authorized user of a vehicle. A next step includes detecting an attempt to start a vehicle without an authorized coded starting device. A next step includes placing a telephone call using a vehicle communication device to a service operator requesting service. A next step includes calling the vehicle by the service operator. A next step includes confirming the particular user of the vehicle using the stored information. A next step includes authorizing the starting of the vehicle. Unauthorized coded starting devices can include a non-programmable key, an unprogrammed programmable key, and a code scanning device.

Abstract: It is possible to start engine economically and easily without deteriorating the theft prevention function even when an engine start key is lost. A vehicle theft prevention system includes permission tools (5C, 5D) for permitting rewrite or write-in of an ID code. The system has a start key registration function for corresponding the ID code of an engine key (5) to the ID code of an immobilizer control section (17), so that the engine key (5) functions as an engine start key (5A, 5B) when the ID code of the permission tools (5C, 5D) is correlated with the ID code recorded in the immobilizer control section (17) and matching is established. Accordingly, when the engine start key is lost or the like, a new engine start key is created for starting the engine economically and easily without requiring replacement of the entire theft prevention device.

Abstract: A smart key system for a vehicle determines that a mobile communicator is not in the passenger compartment and that an in-trunk communicator communicates with the mobile communicator when the trunk gets locked. Then the smart key system executes a recovery process for the mobile communicator locked in the trunk.

Abstract: Herein disclosed is an in-vehicle apparatus controlling system, comprising: an in-vehicle controlling apparatus for controlling an in-vehicle apparatus, and memory media having user identification information stored therein, the user identification information being partially constituted by biometric information indicative of a person demanding permission to utilize the in-vehicle apparatus, wherein the in-vehicle controlling apparatus includes: biometric information obtaining means for obtaining biometric information indicative of the person demanding permission to utilize the in-vehicle apparatus; storing means for storing user identification information which is partially constituted by biometric information indicative of a registered user having permission to utilize the automotive vehicle; identifying means for judging whether or not the person is identical to the registered user having permission to utilize the automotive vehicle by establishing the verification of the biometric information obtained by

Abstract: A system for providing stand-off biometric verification of a driver of a vehicle while the vehicle is moving and/or a person on foot at a control gate, including an RFID vehicle tag reader, an RFID personal smart card reader and a facial detection and recognition (verification) system. The driver carries a RFID personal smart card that stores personal information of the driver and a face template of the driver. The vehicle carries a RFID vehicle tag that stores information regarding the vehicle. When the vehicle approaches the control gate, the RFID vehicle tag reader reads data from the RFID vehicle tag and the RFID personal tag reader reads data from the RFID personal smart card. The facial detection and verification system scans and reads a facial image for the driver. All the data and facial images detected by the readers are sent to a local computer at the control gate for further processing (final face verification).

Abstract: A system for providing stand-off biometric verification of a driver of a vehicle while the vehicle is moving and/or a person on foot at a control gate, including an RFID vehicle tag reader, an RFID personal smart card reader and a facial detection and recognition (verification) system. The driver carries a RFID personal smart card that stores personal information of the driver and a face template of the driver. The vehicle carries a RFID vehicle tag that stores information regarding the vehicle. When the vehicle approaches the control gate, the RFID vehicle tag reader reads data from the RFID vehicle tag and the RFID personal tag reader reads data from the RFID personal smart card. The facial detection and verification system scans and reads a facial image for the driver. All the data and facial images detected by the readers are sent to a local computer at the control gate for further processing (final face verification).

Abstract: A shelf arrangement has a multiplicity of shelf units, each shelf unit having a receiver and a processor coupled thereto. Each receiver is set up to receive data from a data transmission unit fitted on an object which is to be arranged or is arranged in the respective shelf unit. Each processor is set up such that it can determine the position of the shelf unit's processor within the shelf arrangement by virtue of messages being interchanged by processors in directly adjacent shelf units.

Abstract: A paging device and method of use are provided. In one form, a paging device for facilitating intimate contact at a stimulation site of a wearer includes a pager including a vibration mechanism responsive to a pager signal received by the pager. The paging device further includes a housing enclosing the pager and the vibration mechanism. The housing conforms to an undergarment of a wearer to provide intimate contact along a stimulation site of the wearer.

Abstract: RFID tags transmit data preceded by easily detectible preambles, and RFID readers detect such preambles. The preambles of the invention are easily detectible by being specially constructed to have a corresponding autocorrelation diagram with a relatively unambiguous autocorrelation peak. In addition, the preambles may concurrently encode FM0 symbols, while even maintaining a zero mean balance.

Abstract: A tag conflict avoidance method and system are provided. The tag conflict avoidance system includes a plurality of tags receiving a first signal, converting identification codes of the tags into predetermined codes according to the first signal, and outputting the converted codes as second signals; and a reader outputting the first signal, receiving the second signals, and identifying the tags using the codes included in the second signals.

Abstract: A method and system managing radio frequency identification (RFID) systems. The system monitors the performance of systems that use RFID tags and readers. It operates at multiple levels to ensure the optimal performance of readers, tags, antennae, and the information processing systems that acquire and convey tag data. The management system may employ artificial intelligence techniques such as genetic algorithms, fuzzy logic, neural networks, Bayesian networks, support vector machines or statistical methods to develop, maintain and exploit models of RFID system behavior. By comparing the actual performance of RFIDs and related components, the management system can detect and report failures and partial failures of components. The management system may also send signals to components to enhance performance of the overall RFID system.

Abstract: A radio frequency identification device includes an integrated circuit including a receiver, a transmitter, and a microprocessor. The receiver and transmitter together define an active transponder. The integrated circuit is preferably a monolithic single die integrated circuit including the receiver, the transmitter, and the microprocessor. Because the device includes an active transponder, instead of a transponder which relies on magnetic coupling for power, the device has a much greater range.

Abstract: A label printer applicator system programs labels having integrated circuits therein and applies the labels to a package. The applicator includes a tamp assembly having a tamp pad movement assembly and a tamp pad coupled thereto. An RF assembly, including an RF antenna, an RFID engine and antenna cable, is coupled to the tamp assembly. The tamp pad moves from a receiving position, where it receives a non-programmed label, to an extended position, where it applies the label to a package. The RFID engine provides RFID information to the RF antenna, which sends RFID information signals to the label to program the label. After the RFID label is applied to the package, the RF assembly sends test signals to the RFID label to determine whether the label has been properly programmed.

Abstract: A system and a method for data communication with a vehicle control device include a flash adapter which is inserted with a vehicle key into an ignition lock of a vehicle. Upon insertion into the ignition lock, the vehicle key is authenticated. Subsequently, a comparison between the control device data stored in the key and the vehicle can be triggered by using the flash adapter.

Abstract: This invention provides a theft prevention method and device for a vehicle in which before a battery voltage falls to the extent that releasing of a theft prevention system is impossible, the battery voltage is read and a warning is issued of a drop in the battery voltage so that a user is allowed to take measures such as replacement or charging of the battery and the system can be released without trouble for the start of the engine at the time of driving. A theft prevention method for a vehicle, allowing that a main switch 5 connected to a battery 6 is turned on to actuate theft prevention means 8, 9, 10 and operation of the theft prevention means is stopped through releasing operation, wherein a battery voltage is read immediately after the main switch 5 is turned on, it is determined whether or not the battery voltage is no larger than a given value after the releasing operation, and a warning is issued if the battery voltage is no larger than the given value.

Abstract: A warning device for bicycle mainly includes a magnetic and a coil mechanism. The magnetic mechanism includes a magnetic element assembly, a mounting module, and a holding module movably connected to the mounting module for holding the magnetic element assembly therein. The coil mechanism includes a housing, a coil assembly, a rectifier unit, a plurality of light-emitting elements, and a connecting module. The coil assembly, the rectifier unit, and the light-emitting elements are electrically connected to one another and then received in the housing. The mounting module of the magnetic mechanism is fixedly mounted on a fixed part of a bicycle close to a wheel thereof, and the connecting module of the coil module is fixedly connected to two spokes of the wheel, such that the magnetic element assembly and the coil assembly are located at corresponding radial positions relative to the wheel.

Abstract: A communication control apparatus of the present invention controls communication among a plurality of electronic devices mounted on a vehicle and mainly includes a control unit that is configured of a micro computer or the like and that periodically outputs clock pulses, a trouble detecting unit to detect a trouble in the control unit, and a communication control unit to interrupt communication upon detection of a trouble, that is, to control communication by disconnecting an electronic device. The trouble detecting unit includes an analog amount converting unit to convert clock pulses from the control unit to an analog amount and an analog amount comparing unit to compare the analog amount generated in the analog amount converting unit with a predetermined threshold.

Abstract: A system (10) and method manages battery (13) power in a wheel module (11) for indicating when air pressure in a tire falls below a recommended value. Tire air pressure is sensed with a pressure sensor (16). Tire air temperature is sensed with a temperature sensor (18). A determination is made whether the air pressure is increasing or decreasing with respect to time. Based upon whether a ratio of the air pressure and the air temperature is increasing, decreasing or remaining constant with respect to time, tire motion is inferred without directly sensing acceleration or movement of the tire. Power management circuitry (14) controls battery power to enable sensing of air pressure and air temperature at measurement intervals that are longer in time when the tire is not in motion.

Abstract: A method of testing the operational status of remotely distributed hazardous condition detectors is provided. The method utilizes the detector's self-test button to initiate a detector self-test. Once the self-test is complete, the detector's alarm is silenced and a remote self-test signal is sent to the interconnected remote hazardous condition detectors. The remote detectors, on receipt of this signal, will initiate a self-test of their own as if a user had depressed their test button. The user, with the local detector's alarm now silenced, is better able to hear the remotely interconnected detector's alarm. To verify that the remote self-test signal is received, thus verifying the operational integrity of the communications link, the remote detectors may sound an alarm pattern indicative of the receipt of the signal before initiating their self-test.