Abstract: A battery assembly for use in an electric aircraft, the battery assembly including a plurality of battery cells, four opposite and opposing sides, where at least two sides are angled inward as to secure the plurality of battery cells inside the battery assembly, and at least a sensor, where the at least a sensor is configured to detect a thermal runaway.

Abstract: A method and apparatus for monitoring operational parameters in an IoT device is provided. An exemplary method includes performing a statistical analysis of a system metric. A determination is made as to whether an alert limit has been breached. If so, a message is constructed and dispatched to a server.

Abstract: An energy storage module includes a plurality of energy storage devices electrically connected together in series; and a plurality of electronics boards distributed across the module, in electrical contact with one or more of the energy storage devices. The module further includes a plurality of flexible printed circuit boards whereby each of the plurality of electronics boards are electrically connected together in series with a neighboring one of the plurality of electronics boards by a different one of the flexible printed circuit boards. For each electronics board and for each flexible printed circuit board, a ground plane is provided, whereby the ground planes provide electrical grounding at substantially the same potential across all the electronics boards and all the flexible printed circuit boards.

Abstract: A display device includes a display configured to display a deterioration degree of a secondary battery and a controller. The controller is configured to control the display such that the display does not display the deterioration degree when the deterioration degree is lower than a first level, or configured to control the display such that the display does not display the deterioration degree when the deterioration degree is higher than a second level that is higher than the first level.

Abstract: A smart charging device includes a plurality of charging regions, and each charging region includes DC charging sockets disposed therein and configured to charge the mobile electronic devices. The smart charging device includes a to-be-charged device connection detection module, a power detection module, an abnormal detection processing module, a power overload processing module, a periodic alternating charging module, an abnormal charging processing module, a to-be-charged module, a remaining power charging module. These modules can process various conditions of the mobile electronic devices during charging process, so as to take turn to charge the external mobile electronic devices by allocating time to the charging regions, and implement power management mechanism.

Abstract: An input protection circuit includes a current detection circuit, a voltage detection circuit, a latch circuit and an output circuit. The current detection circuit receives a power input, and when an input current exceeds a threshold current, the current detection circuit outputs a control current. The voltage detection circuit is coupled to the current detection circuit, and when the input voltage exceeds a threshold voltage, the voltage detection circuit outputs a control voltage. The latch circuit is coupled to the current detection circuit and the voltage detection circuit. When the latch circuit receives the control voltage or the control current, a switching voltage outputted by the latch circuit is equal to a reference voltage. The output circuit is coupled to the current detection circuit, the voltage detection circuit and the latch circuit. When the switching voltage is equal to the reference voltage, the output circuit stops outputting a power output.

Abstract: A smart electronic system is disclosed. The system can analyze any input voltage to determine whether the input voltage is sufficient to charge the battery of an electronic device and/or to operate the electronic device. If not, the cable is capable of transforming the input voltage to a voltage sufficient to charge and/or operate. The electronic device may be incorporated into the housing of the smart electronic system, and can be any known mobile devices.

Abstract: In a multi-sensing, wirelessly communicating learning thermostat that uses power-harvesting to charge an internal battery, methods are disclosed for ensuring that the battery does not become depleted or damaged while at the same time ensuring selected levels of thermostat functionality. Battery charge status is monitored to determine whether the present rate of power usage needs to be stemmed. If the present rate of power usage needs to be stemmed, then a progression of performance levels and/or functionalities are scaled back according to a predetermined progressive power conservation algorithm. In a less preferred embodiment, there is a simple progressive shutdown of functionalities turned off in sequence until the desired amount of discharge stemming is reached. Battery charge preservation measures are also described for cases when an interruption of external supply power used to recharge the battery is detected.

Abstract: An electronic shelf label system is provided. There is provided a method in which an electronic shelf label periodically transmits its remaining battery capacity to a server in a electronic shelf label system according to the present invention, and the server converts the battery level into a remaining battery life (time) and provides the same, so that a manager can check the remaining battery life in a management mode of the server and a terminal, and easily manage an electronic shelf label using a battery.

Abstract: Some embodiments of the present disclosure relate to a sensor interface module. The sensor interface module includes a comparator having a first comparator input, a second comparator input, and a comparator output. A current- or voltage-control element has a control terminal coupled to the comparator output and also has an output configured to deliver a modulated current or modulated voltage signal to an output of the sensor interface module. A first feedback path couples the output of the current- or voltage-control element to the first comparator input. A summation element has a first summation input, a second summation input, and a summation output, wherein the summation output is coupled to the second comparator input. A supply voltage module provides a supply voltage signal to the first summation input. A second feedback path couples the comparator output to the second summation input.

Abstract: Embodiments of an electronic circuit for monitoring a battery stack enable cell balancing while conserving pin-count of the circuit package. The illustrative electronic circuit comprises a battery monitoring integrated circuit configured for monitoring a plurality of cells in the battery stack. The battery monitoring integrated circuit is arranged to share a common node pin between two adjacent battery cells in the battery stack for the purpose of cell balancing.

Abstract: The present invention relates to a device and method for displaying the lifecycle of a surge protection device, and more particularly to a device and method for displaying the lifecycle of a surge protection device, which detects an increase in leakage current according to a deterioration in performance of the surge protection device in order to provide notice of a replacement time for the surge protection device. According to the present invention, it is possible to for a user to provide notice of a replacement time by displaying the lifecycle of a surge protection device (SPD) to the outside. Additionally, as another effect of the present invention, it is possible to confirm an amount of leakage current flowing into the ground of the SPD and whether the SPD is properly installed on a ground line by using a current and ground state detecting sensor.

Abstract: The disclosed embodiments provide a system that facilitates the use of an electronic device. The electronic device may be a keyboard, a mouse, a trackpad, a remote control, a mobile phone, a wireless phone, a toy, a portable media player, a game controller, and/or a camera. During operation, the system monitors a state-of-charge of a battery used to power the electronic device. Next, the system calculates a charge threshold associated with a low-battery warning for the battery based on the monitored state-of-charge. If the state-of-charge of the battery reaches the charge threshold, the system generates the low-battery warning.

Abstract: A protection system is described herein for an electrical connector providing power to a grounded aircraft. The system includes receiving a sensing device electrically coupled to each of a number of power conductors. The sensing device generates an operating parameter. The system also includes a protection device that measures the operating parameter, determines that the operating parameter exceeds a threshold, and sends an overcurrent notification. The system may also include a shunt that is electrically coupled to the power conductors and generates a different operating parameter. The protection device may determine a difference between operating parameters of the shunt and sensing device and send an overtemperature notification when the difference exceeds an operating threshold. The system may also include a ground fault detection device. Some or all components of the system may be located in a removable adapter.

Abstract: A discharge control apparatus in an electric motorcycle includes a main battery; a motor driven based upon electric power supplied from the main battery and a lighting device that is a load other than the motor for consuming electric power. A BMU determines a remaining capacity of the main battery. A control member performs a discharge control of the main battery for supplying electric power to the motor and the lighting device. The BMU and the control member allow the discharge of the main battery until the remaining capacity becomes a threshold value higher than zero. When the control member receives an instruction of checking a deterioration state of the main battery from an external checking device, the control member performs a discharge of the main battery until the remaining capacity reaches zero, and then, allows the main battery to be fully charged so as to determine a chargeable capacity.

Abstract: An apparatus for managing a battery pack for a vehicle includes a temperature measurement module for measuring temperature of the battery pack; a current measurement module for measuring a charge/discharge current of the battery pack when the measured temperature is not within a predetermined temperature range; a time measurement module for measuring the time while the measured charge/discharge current is over a predetermined current value; a storage module for accumulating and storing the measured time; and a control module for determining a state of the battery pack according to the accumulated and stored time and providing the state information to a user.

Abstract: A fuel battery system is comprised of a power source circuit, a rotating electrical machine that is a load, a memory device and a control unit. Here, a battery learning system corresponds to an arrangement including a fuel battery that is a structural component of the power source circuit, a high frequency signal source, an electric current detection means, a voltage detection means, the memory device and a battery learning part that is a structural element of the control unit. An impedance value can be obtained from alternating current components of respective detecting values of the electric current detection means and the voltage detection means. The battery learning unit has an I-V characteristic curve learning module that learns an I-V characteristic curve and a learning prohibition judgment module that judges whether or not an acquiring interval of the impedance value is over a predetermined threshold interval set in advance, and prohibits learning if the former is over the latter.

Abstract: A method for measuring electrical resistance of a joint includes supplying a first current between a first end of a first member of the joint and a first end of a second member of the joint. The method also includes measuring a first voltage between a second end of the first member and a second end of the second member. The first ends of the first member and the second member are oriented or situated opposite of the joint from the second ends of the first member and the second member. The method also includes calculating a first joint resistance of the joint from the supplied first current and the measured first voltage.

Abstract: A charging circuit is provided that charges a battery for supplying power to a motor drive system that includes a three-phase motor and a three-phase inverter for controlling the three-phase motor. The three-phase inverter includes first to third sets of switching elements. Each set corresponds to one of the three phases. The charging circuit includes a single-phase output transformer, a rectifier circuit, a line, and a controller. The single-phase output transformer includes a secondary side output section having a first terminal and a second terminal. The rectifier circuit is connected in parallel with the three-phase inverter and the battery. The rectifier circuit is also connected to the first terminal of the secondary side output section. The line connects a connecting point between the first set of the switching elements in the three-phase inverter with the second terminal of the secondary side output section. The controller performs on-off control of the first to third sets of the switching elements.

Abstract: It is possible to prevent charge of an incompatible secondary cell while suppressing the size of a mobile electronic device and a secondary cell without increasing power consumption so as to prevent damage of the secondary cell or the mobile electronic device by charge. A detachable secondary cell (30) supplies power to a mobile electronic device (2). The mobile electronic device (2) includes: a cell terminal (60) which outputs and inputs power to/from the mounted secondary cell (30); non-contact information extraction means (20) which performs a magnetic field communication; a loop antenna (26) which transmits/receives a signal using an electromagnetic wave by the non-contact information extraction means (20); and control means (22) which acquires particular information outputted from the non-contact information extraction means (20) and controls charge of the secondary cell (30) according to the acquired particular information. The loop antenna (26) is arranged in the cell terminal (60).

Abstract: A battery alarm for use with a battery assembly is provided, the battery alarm including a first activation component, a signaling component, and an output component. The first activation component is configured to activate the alarm upon disengagement of the battery assembly from a battery-operated device and is further configured to deactivate the alarm upon engagement of the battery pack with the battery-operated device. The signaling component is coupled to the first activation component and is configured to transmit a signal when the alarm is activated. The output component is adapted to receive the signal from the signaling component and is configured to produce a visual, audible, and/or tactile output upon receipt of the signal from the signaling component.

Abstract: Various embodiments of systems, methods and apparatus are provided for adjusting a low battery detection threshold in a remote control. An embodiment of a method includes determining a type of a battery powering a remote control of an entertainment device and determining a first low battery threshold for the battery based on the type of the battery. The first low battery threshold indicates a low battery condition of the remote control. Responsive to measuring a voltage of the battery, a determination is made regarding whether the voltage of the battery is below the low battery threshold. Responsive to determining that the voltage of the battery is below the first low battery threshold, a low battery message is transmitted to an entertainment device. The entertainment device utilizes the message to present an indicator to a user regarding the low battery condition of the remote control.

Abstract: A method and apparatus for determining coolant leakage in a vehicular propulsion system battery. An AC isolation resistance test is used to determine whether an isolation fault has occurred within the battery, but can also determine the capacitance of the circuit or system, which can further determine the coolant leakage levels of the vehicular propulsion system battery. This eliminates having an additional device to measure the coolant leakage.

Abstract: A method and apparatus are provided to indicate battery capacity status. Different blinking frequencies of an LED correspond to different battery states of charge. Furthermore, the present invention provides a smooth visual brightness change of the LED by providing the appropriate LED current according to human eye characteristics.

Abstract: An apparatus for sensing leakage current of a battery includes a current sensing resistance installed on a current detection path of positive and negative terminals of a battery; a DC (Direct Current) voltage applying unit for inducing a potential difference with an opposite polarity to the current detection path through the current sensing resistance; and a leakage current determining unit for sensing a magnitude of current flowing through the current sensing resistance according to the induced potential difference on the current detection path, and determining based on the sensed magnitude of current whether leakage current occurs.

Abstract: A method of providing assistance for locating a radio-frequency identification (RFID) device is provided. The RFID device preferably comprises a power source having a power level and a feedback device. The method comprises determining the power level of the power source is below a first predetermined power level, and transmitting a first signal that indicates the power level of the power source is below the first predetermined power level. Thereafter, the method comprises receiving a second signal that instructs the RFID device to activate the feedback device, and operating the feedback device in response to receiving the second signal.

Abstract: A system for monitoring batteries comprises a current control element coupled in parallel to a diode and across a battery. The current control element measures current on the cathode end of the diode. Once the voltage potential reaches a threshold, the current control element routes the current from the cathode end of the diode to the anode end of the diode thereby reducing the voltage potential across the battery terminal. Accordingly, a battery sensing element is prevented from falsely sensing a presence of an operable battery due to leakage current of the diode.

Abstract: A system and method of testing charging current of a mobile electronic device sets a charging voltage value and a battery voltage value, and sends a control command to a power supply device to generate the charging voltage and the battery voltage. The system and method further receives a charging current value from a current test device under the charging voltage and the battery voltage. Furthermore, the system and method determine if the charging current value falls in an allowable current range and displays test result on a display device.

Abstract: Cell voltages within a battery pack and a voltage delivered to a load or drive system, along with a current delivered to the system, are monitored and used to detect a possible abnormal condition of a wiring harness.

Abstract: An apparatus for sensing leakage current of a battery includes a voltage distribution node installed on a first conductive line connecting both terminals of a battery; first and second switches installed between the voltage distribution node and positive/negative terminals of the battery; an insulation resistance and a current sensing resistance installed on a second conductive line connecting the voltage distribution node to a ground; a DC voltage applying unit for applying positive/negative DC voltage to a ground-side end of the current sensing resistance to induce potential difference between the voltage distribution node and the DC voltage applying node; and a leakage current determining unit for sensing magnitude of electric current flowing through the current sensing resistance according to the induced potential difference in turning-on state of the switches, and then determining leakage current by checking whether the magnitude of electric current is out of standard level over threshold value.

Abstract: When a battery pack, comprising an overcurrent protection section for stopping, when a current greater than a first threshold value passes, a current supply, is connected to a power supply terminal of an information processing apparatus, the information processing apparatus draws a current greater than the first threshold value. Thereafter, an output current and output voltage of the battery pack are detected, thereby measuring a time period from when a current drawing section draws the current greater than the first threshold value to when the battery pack stops the current supply. When the measured time period is within a first predetermined time range, the battery pack is permitted to supply an electric power. On the other hand, when the measured time period is not in the first predetermined time range, the battery pack is prohibited from supplying the electric power.

Abstract: A voltage sensing device with which high-precision voltage sensing is possible without the need to obtain a unique correction constant for each device. A pair of voltage input nodes NCk and NCk-1 is selected from voltage input nodes NC0-NCn in switch part 10, and they are connected to sensing input nodes NA and NB in two types of patterns with different polarity (forward connection, reverse connection). Sensing input nodes NA and NB are held at reference potential Vm by voltage sensing part 20, and current Ina and Inb corresponding to the voltage at voltage input nodes NCk and NCk-1 flows to input resistors RIk and RIk-1. Currents Ina and Inb are synthesized at different ratios in voltage sensing part 20, and sensed voltage signal S20 is generated according to the synthesized current Ic. Sensed voltage data S40 with low error is generated according to the difference between the two sensed voltage signals S20 generated in the two connection patterns.

Abstract: A method and apparatus are provided to indicate battery capacity status. Different blinking frequencies of an LED correspond to different battery states of charge. Furthermore, the present invention provides a smooth visual brightness change of the LED by providing the appropriate LED current according to human eye characteristics.

Abstract: A method for detecting operations of a power storage device is disclosed. The power storage device includes an electricity storage unit for storing power output from an electronic device or outputting power to the electronic device. The method includes detecting current between the electricity storage unit and the electronic device to determine whether the electricity storage unit is malfunctioned and causes short circuit, and generating an alarm signal when the electricity storage unit is malfunctioned and causes short circuit.

Abstract: Various embodiments of systems, methods and apparatus are provided for adjusting a low battery detection threshold in a remote control. An embodiment of a method includes determining a type of a battery powering a remote control of an entertainment device and determining a first low battery threshold for the battery based on the type of the battery. The first low battery threshold indicates a low battery condition of the remote control. Responsive to measuring a voltage of the battery, a determination is made regarding whether the voltage of the battery is below the low battery threshold. Responsive to determining that the voltage of the battery is below the first low battery threshold, a low battery message is transmitted to an entertainment device. The entertainment device utilizes the message to present an indicator to a user regarding the low battery condition of the remote control.

Abstract: Shielded power and power extension cords are protected from fire and other hazards caused by deterioration which may be due to age and/or excessive heat, or to physical damage which may be caused by kinking or crushing. At least one shield, which may surround multiple conductors or a single conductor is grounded through a fuse and made to function as a sensor in a fault detection circuit that opens the fuse and causes a relay to discontinue cord power transmission when a fault current passes from an ungrounded conductor to the shield. The relay circuit also refuses to fully close its contacts that transfer power to the cable in the event of receptacle wiring error and functions as a buzzer to indicate such an error.

Abstract: A plurality of battery cells is connected in series via a plurality of bus bars. An FPC board is attached to the bus bars. On the FPC board, PTC elements are respectively arranged in close proximity to the bus bars. Each of conductor lines on the FPC board extends between an attachment portion of the bus bar and the PTC element arranged in close proximity to the bus bar, extends between the PTC element and one end of the FPC board, and is connected to a plurality of connection terminals of a printed circuit board. The connection terminals are electrically connected to a detecting circuit.

Abstract: A sensor includes a detector circuit configured to measure current, voltage, and temperature of a battery. A processor is in communication with the detector circuit and is configured to convert the current, voltage, and temperature into battery information. A transmitter is in communication with the processor and is configured to wirelessly transmit the battery information. A receiver is in wireless communication with the transmitter and is configured to receive the battery information and control an external component in response to the battery information. A method includes measuring the current, voltage, and temperature of the battery, converting the current, voltage, and temperature into battery information, wirelessly transmitting the battery information to the receiver, and controlling the external component in response to the battery information.

Abstract: A design structure embodied in a machine readable medium used in a design process includes a circuit that employs an anti-tamper sensor. The circuit employs an anti-tamper sensor that includes a circuit element that is responsive to a first input and to a second input. A selective coupling element couples the circuit element to the first input and is responsive to the anti-tamper sensor. The selective coupling element has a first state that allows the circuit element to operate normally when the anti-tamper sensor does not detect a tamper condition and is configured to enter a second state that causes the circuit element to become inoperable when the anti-tamper sensor detects a tamper condition. A decoy coupling element is disposed between the second input and the circuit element and has an appearance corresponding to the selective coupling element.

Abstract: An intelligent adaptive energy management system and method for an electronic device such as a cell phone or laptop computer. The system comprises at least two batteries that work cooperatively. The system includes multiple features that may be used alone or in combination. One feature includes one or more sensors capable of measuring various characteristics of the battery cells such as temperature, voltage, and shape deformation. The sensors communicate the measured data to a control module which may control cell charging, cell discharging, cell balancing, and/or terminating the use of one or more of the cells. A second feature is to enhance the scalability of the batteries by making the battery cells logically and/or physically removable and configurable so that the capacity of the batteries can be scaled on demand. A third feature is to provide intelligent charging and discharging methodologies. One alternate discharge method discharges the cells intelligently using measured rotational turns.

Abstract: A battery warranty and metrics tracking network with a programmable battery product for storing, sending and receiving data from a battery warranty, enablement, and metrics tracking network, having an at least one onboard electronics module and storage media on the battery product, an at least one point of sale/point of maintenance device providing communication with the battery product and communicating data from the battery product and to the battery product, an at least one network communicating data from the programmable battery product and to the programmable battery product and an at least one product warranty and features database in communication with the network, the database including storage of data from the programmable battery product and communication of stored data to the battery product to enable or disable the programmable battery product or enable or disable features on the battery product based on the information communicated to or from the programmable battery product or the at least one p

Abstract: A circuit that employs an anti-tamper sensor includes a circuit element that is responsive to a first input and to a second input. A selective coupling element couples the circuit element to the first input and is responsive to the anti-tamper sensor. The selective coupling element has a first state that allows the circuit element to operate normally when the anti-tamper sensor does not detect a tamper condition and is configured to enter a second state that causes the circuit element to become inoperable when the anti-tamper sensor detects a tamper condition. A decoy coupling element is disposed between the second input and the circuit element and has an appearance corresponding to the selective coupling element. The decoy coupling element will cause the circuit element not to operate normally if the decoy coupling element has a selected physical property of the selective coupling element in the first state.

Abstract: The invention provides a system and battery including a state-of-charge indicator (SOCI) to monitor and display the amount of charge within the battery. The SOCI is capable of operating in a hibernate mode, an active mode, and/or a sleep mode. The battery may be manufactured, shipped and/or stored with the SOCI operating in a power-saving hibernate mode. The SOCI may exit the hibernate mode and begin operating in active mode if a physical key connected to the battery is removed. In addition, the SOCI may operate in a sleep mode while the battery is not being used to conserve power. Furthermore, the invention provides a method of making a battery including a SOCI to monitor and display the state of charge of the battery.

Abstract: An apparatus and method for monitoring at least one battery condition. An ac signal is applied to a battery. A difference between a signal output from the battery and a threshold determines a battery condition. The determined battery condition is transmitted remotely from the battery location either wirelessly or through a network to controller and/or is visibly displayed at the battery location.

Abstract: An electrical accessory charging compartment, an interface device and a retrofit for creating a charging compartment and a cabinet with an lectrical accessory charging compartment on its exterior. A plurality of electrical connections is located in the charging compartment for supplying electricity to a plurality of consumer electronic devices simultaneously. A plurality of data connections is located in the charging compartment for transmitting data to and from the plurality of consumer electronic devices simultaneously. The interface device for a plurality of consumer electronic devices is provided with a connector member having a plurality of outlets arranged to supply electrical power and provide data connections to a plurality of consumer electronic devices, and a data connector arranged to be connected to a data network.

Abstract: A status indicator indicates an operating state, including an electrical malfunction, of an electrical load that is located and controlled from locations remote from a monitoring location.

Abstract: In an embodiment of the present invention, a clamp-on sensor is coupled at a single point of a battery string in an un-interruptible power supply. In embodiments of the present invention, the clamp-on sensor is a Hall effects sensor for sensing ripple current through the battery string. The clamp-on sensor is coupled with a logic circuit for detecting a battery failure of the battery string. In response to detecting a failure of the battery string, the logic circuit automatically generates a message over a communication network indicating the failure of a battery in the battery string. In embodiments of the present invention, the logic circuit can also generate a message indicating the failure of an inverter in the un-interruptible power supply.

Abstract: A diagnostic system in which, at every point in time, a forecast is made of the future response times of each EPP (End-to-end Probe Platform) probe in a battery of probes. Thresholds are established in terms of the distribution of future EPP values. The theory of Generalized Additive Models is used to build a predictive model based on a combination of a) data normally generated by network nodes, b) results of a battery of probes and c) profile curves reflecting expected response times (i.e. based on recent history) corresponding to this battery for various times of day, days of week, month of year, etc. The model is pre-computed, and does not have to be dynamically adjusted. The model produces, at regular intervals, forecasts for outcomes of various EPP probes for various horizons of interest; also, it produces thresholds for the respective forecasts based on a number of factors, including acceptable rate of false alarms, forecast variance and EPP values that are expected based on the recorded history.

Abstract: A circuit powering an electrical device based on a commanded current signal is provided. The circuit includes a linear current amplifier which sets a desired current flow. The circuit also dynamically controls a supply voltage in order to minimize power dissipation of the linear current amplifier. The circuit may also include a voltage drop measurement amplifier, a voltage shaping amplifier, and a switching power supply. The circuit is useful for controlling electrical devices requiring precise current control and minimal power dissipation, for example, driving light-emitting diodes (LEDs) that provide illumination inside the passenger compartment of a vehicle for an imaging occupant detection system.

Abstract: An electrically operated equipment with a sealed enclosure containing circuitry with an exterior visual indicator to show a state of operation of the equipment. The visual indicator is illuminated by a magnetic flux sensor also exterior to the equipment, the sensor inducing an electrical current from a sensed magnetic flux passing through a permeable wall of the enclosure. The magnetic flux is provided by a magnetic field generator within the enclosure. The generator is connected to the equipment to generate the field when the circuitry is operating correctly whereby the indicator shows a correct state of operation. The invention avoids the use of sealed orifices in the enclosure for conductors to pass to exterior LEDs or LEDs sealed within the enclosure and possible resultant leakage. The invention is useful for optical network units. The invention also includes a visual indicating device of multi-layer configuration and a method of visually indicating the operational state of circuitry.