Abstract: A system, method and computer program product that permits a user, using the fingers of a single hand, to produce defined outputs such as generating characters for text input and executing commands. In a data processing system having plural input detectors, the invention comprises permitting the user to perform sequential gestures with the fingers of one hand to produce the defined outputs.

Abstract: The invention concerns a method (200) of generating an array (100, 300, 400) having a reduced number of input/outputs (114, 314, 414). The method includes the steps of, for each array row input/output, grouping (212) at least one set of rows (124, 324, 424) in which the set of rows is coupled to the array row input/output and, for each combination of the array row input/outputs, selectively coupling (216) non-set rows (326, 426) to the array row input/outputs that comprise the combination. At least a portion of a number of rows (110, 310, 410) for the array is equal to the number of rows in each set of rows multiplied by the number of array row input/outputs plus the number of non-set rows coupled to the array row input/output combinations.

Abstract: An apparatus and method is disclosed for providing a fast, low power consumption, detection of at least one depressed key in a resistive matrix keyboard. The common contact of each row of a resistive matrix is connected to a first input of each of a plurality of analog/digital comparators capable of switching between high and low voltage states. A common predetermined reference voltage is applied to a second input of each analog/digital comparator using a digital to analog converter. The output of a analog/digital comparator is in a first state if the voltage level applied to the first input is higher than the reference voltage, and in a second state if the voltage level applied to the first input is lower than the reference voltage. The reference voltage is varied to identify which analog/digital comparator has experienced a change of state.

Abstract: An improved key matrix scanning technique conducts a first pre-scan on a first array of connections in a key matrix to identify any activated keys or buttons associated with the first array. A second sub-scan is conducted on a second array of connections in the key matrix but only for the connections in the first array that are detected as having activated keys.

Abstract: A key switch 102 formed by arranging a plurality of key contacts SW11, SW12, SW21, SW22, . . . at cross points of a key matrix is provided with a power supply control key (SW11), and a key scan circuit 101 for detecting open/close states of the plural key contacts of the key switch 102 is independently arranged from a power supply control key state detecting means for detecting the open/close state of the contact SW11 of the power supply control key. The depression of the power supply control key (SW11) is detected by the power supply control key state detecting means. When the operation is ended, or the power supply is turned OFF, the depression of the power supply control key is detected by the key scan circuit 101, and the supply of the electric power is stopped.

Abstract: Aspects of a switch matrix circuit are provided. In accordance with a circuit aspect, a plurality of switches are organized in a row and column configuration. Coupled to the plurality of switches is a current sensing circuit. The current sensing circuit includes a transistor and at least one resistor per column of the plurality of switches. Current amplified by the transistor and converted by the at least one resistor in a column is sensed as a logic level indicative of a switch status within the column for a selected row. The current sensing arrangement may also be used in an embodiment utilizing bi-directional signal control to minimize the number of I/O lines required to scan the switch matrix. The bi-directional signal scanning may also be implemented in another embodiment that senses voltage levels to determine switch closures.

Abstract: A keyboard scan engine integrated on a chipset to initiate a keyscan process. The keyboard scan engine detects a key depression. When in a trusted mode, the keyboard scan engine transmits a key code, corresponding to the key depression, through a trusted internal bus interface. When in a non-trusted mode, the keyboard scan engine transmits the key code through an interface to be processed by an onboard keyboard controller.

Abstract: A test method for testing a wireless human input device being totally implemented in program codes which are built in the input device is disclosed. A step (A) is to start a test of transmission quality of the input device. A sub step (a1) is to judge whether received pressing signals obtained by pressing a series of keys of a wireless emitting device are same as some predetermined activating-for-testing pressing signals. A sub step (a2) is to execute a step (B) if the step (a1) is true, otherwise to execute a step (C). A step (B) is to execute a working-mode test of the input device. A sub step (b1) is that the emitting device transmits some sequential test data. A sub step (b2) is that a wireless receiving device of the input device receives the test data from (b1), then the test data are transmitted to an electronic machine connecting to the receiving device. A sub step (b3) is that the electronic machine outputs result data of testing in corresponding to the test data.

Abstract: A system and method for scanning a data-input array (e.g., a keyboard or keypad) using a reduced number of signals is disclosed. Specifically, a switch array is disclosed comprising a plurality of switches and a plurality of input/output (I/O) lines. The switch array is arranged in an N*N matrix. A plurality of N I/O lines is used to scan the matrix. In one embodiment, the switches in the array are arranged in an N*(N?1)/2 configuration. In this configuration, there is no duplication of circuit paths. In another embodiment, the switches in the array are arranged in an N(N?1) configuration. In this configuration, a plurality of diodes are used to identify an activated switch depending upon which of a plurality of signal paths is activated. The plurality of diodes is included to differentiate between pairs of switches that complete the same paths between pairs of I/O lines.

Abstract: A device for activating a control unit is proposed. It includes at least one operating element operable by a user as well as analog encoding means assigned to the operating element. To generate an activation signal for a control unit, deactivation means are provided that deactivate at least one analog encoding means in order to digitally encode the operating element.

Abstract: An apparatus and a method for determining output signals according to pressure and depressing time mainly includes a timer, a scanner and a keyboard connecting electronically to the timer and the scanner. The keyboard has a plurality of button keys. When in use, the timer is set to zero and stops counting time. Then the scanner scans the keyboard to locate the button key being depressed by an external force. A signal is output depending on the external force. A first signal is output when the external force is small. When the external force is large and the time counted by the timer does not exceed a selected time period, the first signal is output. When the time counted by the timer exceeds the selected time period, a second signal is output. Thus input information may be entered through fewer button keys, and injury that might otherwise occur by using composite keys may be avoided.

Abstract: An apparatus for data input. The apparatus comprises a sensing circuit for a plurality of keys, outputting an interruption signal and a corresponding group of data bits when one of the keys is pressed, a shift register circuit receiving a strobe signal, a clock signal and the group of data bits in parallel from the sensing circuit when the strobe signal is asserted, and serially outputting the group of data bits in synchronization with the clock signal, and a microcontroller receiving the interruption signal, outputting the strobe signal and clock signal when the interruption signal is asserted, and serially receiving the group of data bits from the shift register circuit to identify the key being pressed.

Abstract: A handheld electronic device includes a reduced QWERTY keyboard and is enabled with disambiguation software. The device provides output in the form of a default output and a number of variants. The output is based largely upon the frequency, i.e., the likelihood that a user intended a particular output, but various features of the device provide additional variants that are not based solely on frequency and rather are provided by various logic structures resident on the device. The device enables editing during text entry and also provides a learning function that allows the disambiguation function to adapt to provide a customized experience for the user. The disambiguation function can be selectively disabled and an alternate keystroke interpretation system provided.

Abstract: This invention is a photosite which allows access from a cell phone to provide user-friendlier services. The photosite creates an ID (S6501) and creates a character string Str from the ID by combining numerals and alphabetical characters by using a storage unit which stores buttons 0 to 9 of the cell phone and the number of alphabetical characters assigned to the respective buttons in correspondence with each other (S6502–S6507). In this case, a character string is created such that any two consecutive characters are assigned to different keys.

Abstract: An apparatus has a keyboard panel with a QWERTY array of alphabetic key actuation indicia. The apparatus further has a QWERTY array of keys that are free of alphabetic key actuation indicia, and are located adjacent to corresponding alphabetic key actuation indicia on the keyboard panel. Other parts of the apparatus include an output device responsive to actuation of the keys, and a processing device operatively coupled between the keys and the output device. Summarized alternatively, the apparatus includes a keyboard with keys arranged in arcuate horizontal rows. The keys in each row have centerlines projecting radially from a respective common centerpoint.

Abstract: A keyboard with elevated keys for a notebook computer. The keys of the keyboard are elevated when the notebook computer is opened, and can be depressed when the flat display is closed. The keyboard has keys movably connected to the foundation sheet through scissors-type linking mechanisms. A plurality of guiding sheets is movably disposed on a foundation sheet and has hooks and tracks. Each of the tracks is parallel to a first direction. A sliding member is movably disposed on the foundation sheet and has protrusions extending into each of the tracks. When the sliding member moves in the first direction, the protrusions move the guiding sheets from a first position to a second position. The hooks of the guiding sheets sequentially press the scissors-type linking mechanism of each key to depress the keys of the keyboard from elevated position to depressed position.

Abstract: A key sensing device comprises a first conductive contact and a second conductive contact spaced from one another by a low-force spacer element which includes a low-force aperture disposed between the first conductive contact and the second conductive contact. A third conductive contact and a fourth conductive contact are spaced from one another by a high-force spacer element which includes a high-force aperture disposed therebetween. The low-force aperture and the high-force aperture are configured to be aligned with a keyboard key so that a pressing of the keyboard key with a sufficient force causes contact between the first conductive contact and the second conductive contact through the low-force aperture and contact between the third conductive contact and the fourth conductive contact through the high-force aperture. The low-force aperture is larger in size than the high-force aperture.

Abstract: Apparatus and methods for keyboard data normalization are disclosed. The example apparatus and methods convert physical location dependent keyboard data into keycap dependent data in a pre-boot environment.

Abstract: Apparatus and methods for keyboard data normalization are disclosed. The example apparatus and methods convert physical location dependent keyboard data into keycap dependent data in a pre-boot environment.

Abstract: A logic circuit uses hardware to process keyboard scanning, more especially, a microprocessing system inputs the signal through a pressed key into a control circuit for conducting operation; since the column input end has electric resistance with higher driving ability than that of the row output/input end, a higher electric potential status is thereby obtained and conducted with the circuit through a pressed key to make the high and the lower electric potentials approach in accordance with each other and generate electric potential change, or through a converting method of automatically driving electric potential, the innovative effect of the present invention is achieved.

Abstract: A system for providing a first signal to a flip circuit and receiving a second signal from the flip circuit over an electrical path adapted for use with a keypad having a keypad lighting circuit. The system includes a first circuit for providing the first signal to the flip circuit via a first electrical path, the first signal having alternating first and second states. A second circuit generates a second signal. A third circuit receives the second signal via the first electrical path. The second signal is received during the second state of the first signal. In a more specific embodiment, the first and second states are continuously alternating states. The first signal provides power to the flip circuit when the first signal is in the first state. The first circuit further includes a signal generator for adjusting a duty cycle of the first signal. The signal generator includes a voltage source, a switching circuit connected to the voltage source, and a control circuit connected to the switching circuit.

Abstract: A keyboard scan circuit for a device receiving plural inputs simultaneously is provided. The scan circuit includes a plurality of keyboard input/output ports, each of which can be selected from a group consisting of an input mode, an output mode, and a floating mode for receiving one of a plural inputs, a plurality of rectangular matrices including a plurality of detectable input terminals and a plurality of synchronously detectable input terminals and formed by means of cross-linking the keyboard input/output ports, and a plurality of current-isolating elements electrically connected between the keyboard input/output ports and the rectangular matrices for mutually isolating signals of the rectangular matrices.

Abstract: A keyboard includes a plurality of key elements arranged in rows and columns in a matrix-like manner. Each key element has first and second break contacts which are decoupled for safety reasons and are commonly activated when the key element is actuated. An energy supply unit feeds to an evaluation unit electric energy serially via the first break contacts for each separate column and serially via the second break contacts for each separate row. In this way the location of the key element actuation can be reliably ascertained through column and row detection.

Abstract: A miniaturized single-hand keyboard for computers, PDAs, cellular phones and other portable electronic devices. The keyboard has only four keys, each operated by one finger. Characters are generated by depressing a single key or a combination of two keys in a ‘composite keystroke’. A composite keystroke is performed by depressing a combination of two keys in a predefined order and then releasing them in a predefined order. In the normal mode, three simple keystrokes and 24 possible composite keystrokes are used to generate each of the 26 alphabetic characters and a space. One of the four simple keystrokes (optionally followed by another simple keystroke) is used to enter one of five other modes (Shift, Numeric, Language, Alternate and Control), which support generating uppercase, numeric, language specific and special characters and cursor control and editing control codes.

Abstract: A touch curve memory 110 stores therein a touch curve formed by velocity values corresponding to touch data generated by a keyboard device 20. A correction coefficient generator 10 generates a correction coefficient composed of a ratio of one of the velocity values stored in the touch curve memory corresponding to one of the touch data generated by the keyboard device, in a maximum touch memory mode switched by a mode switch 21 (SW1), to a maximum value of the velocity values in the touch curve memory. A corrector 10 multiplies the correction coefficient generated by the correction coefficient generator by the respective velocity values stored in the touch curve memory, and then generates a touch curve formed by new velocity values. Accordingly, it is possible to provide a touch control apparatus and a touch control method which can obtain a touch curve, from which a touch response suitable for a user can be obtained, easily and in a short time.

Abstract: A keyboard includes a text key zone and a special function key zone, and the special function key zone is further divided into seven major function zones, namely, mouse editing zone, Internet zone, multimedia play zone, application zone, power management zone, numeric and shortcut keys convert and input zone, and indicator zone. The seven major zones are electrically connected to I/O ports of a microcomputer included in an internal circuit configuration of the keyboard and work with a seventh class code that uses definition E2 as leading code. The keyboard enables different kinds of inputs, so that a user may perform professional and convenient operation or document editing directly under a computer operating system without the need of memorizing and combining multiple keys or using a mouse as an aid.

Abstract: A new apparatus for reading keyboard-commands of a portable computer comprises a shift register, a keyboard-matrix circuit, a filter, a buffer, an address generator, a mapping device, a comparator, and an output device. The shift register is for outputting a plurality of scan-input signals and a reference signal. The keyboard-matrix circuit is for outputting a scan-output signal according to the scan-input signals. The keyboard-matrix circuit includes a plurality of nodes corresponded to the keyboard buttons, respectively. The filter is for filtering the noise of the scan-output signal. The buffer is for further stabilizing the filter signal. The address generator is for reading the location of the node corresponding to the button being pressed. The mapping device is for outputting a mapping signal corresponding to the button being pressed. The comparator is for outputting a comparing signal, which represents the command corresponded to the pressed button.

Abstract: A method is provided for recognizing a key in a terminal apparatus having a key matrix structure. The method according to the invention includes the steps of recognizing pushing of and detaching from a key by using a difference between a previous key status value on the key matrix and a current key status value according to a change of the key status, and obtaining a positional value of an inputted key on the key matrix by using a relational expression considering difference values between adjacent rows in each line and between adjacent lines in each row and a difference between the previous key value and the current key value.

Abstract: Method for decreasing the existence of externally detectable revealing signals, so-called {umlaut over (ROS)}, from keyboards (1), e.g. for computers, where the keyboard is fed with signals, so-called matrix signals, which are detected for detection of activity regarding the keys (2) of the keyboard, whereby said matrix signals are generated by means of signal devices. The method is especially characterized in that the matrix signals are high-frequency filtered before they are fed to the keyboard.

Abstract: A controller has means responsive to a continuous press of a continuously operable key to transmit, to an electronic device, a key command indicative of a type of the pressed key, and means for transmitting, to the electronic device, a continuous-key-press command at first time intervals of a predetermined length while the key is kept pressed.

Abstract: An apparatus and method for providing Unicode support in legacy operating systems are provided. With the apparatus and method, a focus hook module, keyboard hook module, and keystroke conversion module are registered with the legacy operating system. The focus hook module determines the currently active application and whether the currently active application is Unicode capable. The keyboard hook module receives keyboard events from an input interface and sends those keyboard events to the keystroke conversion module. The keystroke conversion module converts the keyboard events into Unicode characters which are sent back to the keyboard hook module. The keyboard hook module then stores the Unicode characters in a temporary storage memory, e.g., the clipboard. The keyboard hook module then sends a command to the application to paste the contents of the temporary storage memory to the currently active application.

Abstract: The present invention relates to an integrated circuit (IC) device for a wireless keyboard array that concentrates the circuital functionalities of an oscillation circuit, a transmission/receiving circuit, an array detector, a signal processor, a coder, a decoder, an array decoder, et cetera, to be manufactured as a wireless keyboard array IC to enable the keyboard simultaneously to simultaneously conduct the code transmission and the receiving of the decoding as well as output the signal data keyed in from the keyboard to a keyboard controller by the method of serialization and via the emitting circuit and receiving circuit, then the keyboard controller transmits the signal data into a computer for increasing the practical value of the economic efficiency.

Abstract: A logic state detection system for detecting the state of at least one state changing device includes a scanning circuit and a current detection circuit. The scanning circuit selectively activates at least one output line electrically connected with the at least one state changing device. Current passes through the scanning circuit to the at least one output line that is activated. The current detection circuit determines whether the state changing device is in a conducting or a non-conducting state as a function of the current.

Abstract: An apparatus and method is disclosed for providing a fast, low power consumption, detection of at least one depressed key in a resistive matrix keyboard. The common contact of each row of a resistive matrix is connected to a first input of each of a plurality of analog/digital comparators capable of switching between high and low voltage states. A common predetermined reference voltage is applied to a second input of each analog/digital comparator using a digital to analog converter. The output of a analog/digital comparator is in a first state if the voltage level applied to the first input is higher than the reference voltage, and in a second state if the voltage level applied to the first input is lower than the reference voltage. The reference voltage is varied to identify which analog/digital comparator has experienced a change of state.

Abstract: Method and apparatus for disabling the operation of a computer keyboard with respect to depressed keys as they are observed by the computer's CPU. Entry into, and exit from, the keyboard disabled state is made via specific, simultaneous combinations of depressed keys. In one embodiment of the invention a new software routing (31) is added to the existing keyboard software (12) to recognize specific, simultaneous combinations of depressed keys and alternately inhibit or allow transmissions from the keyboard to the computer CPU in response to depressed keyboard keys. In an alternate embodiment an apparatus (100) is added between an existing keyboard and the computer to similarly recognize specific, simultaneous combinations of depressed keys via a lock detection function (111) which alternately inhibits or allows transmission of keyboard clock (122) and data (123) signals, thus preventing depressed keyboard keys from being recognized by the computer CPU.

Abstract: Letters (more generally, language symbols) are entered electronically by selecting, in sequential fashion, two keys on a standard phone layout. In preferred embodiments, the two keys in the sequence are located in the same row. The first key selected is that key on which the desired letter is displayed, and the second key is given by the spatial position of the desired letter within its group of letters on the key. The letters and keys may be color-coded to aid the user when inputting the two-key sequences. Letters may be selected to spell out words on a screen and then sent electronically to a remote device or recipient.

Abstract: A keyboard has a processor, a scan matrix coupled to the processor, a first set of keys coupled to the scan matrix, a logic control circuit, and a second set of keys coupled to the logic control circuit. The processor decodes the identity of a pressed key from the second set of keys via the logic control circuit.

Abstract: An apparatus and a method for determining output signals according to pressure and depressing time mainly includes a timer, a scanner and a keyboard connecting electronically to the timer and the scanner. The keyboard has a plurality of button keys. When in use, the timer is set to zero and stops counting time. Then the scanner scans the keyboard to locate the button key being depressed by an external force. A signal is output depending on the external force. A first signal is output when the external force is small. When the external force is large and the time counted by the timer does not exceed a selected time period, the first signal is output. When the time counted by the timer exceeds the selected time period, a second signal is output. Thus input information may be entered through fewer button keys, and injury that might otherwise occur by using composite keys may be avoided.

Abstract: A compact key input apparatus interface includes a resistive element and a number of key contacts on the resistive element. The keys of a key input apparatus are disposed to provide electrical contact between a voltage source and the resistive element at a particular contact point when a corresponding key is depressed, such that a path from the voltage source to ground is made through the resistive element. The keys are arranged along the length of the resistive element so that the depression of any key provides a different conductive path to ground and therefore a different magnitude of current through the conductive path. A corresponding sense voltage measured at a sampling point provides a single-line input to a key decoder, which determines which key is depressed based on the level of the sense voltage.

Abstract: A keyboard control apparatus with a USB interface for use in a notebook computer having a number of keys. In one embodiment, a mapping unit is employed to store a number of key matrix codes corresponding to the keys. In accordance with a clock signal and a start signal, a shift register is capable of generating a reference signal and a number of scan output signals. A key matrix circuit then receives the scan output signals to provide a number of scan input signals. An address generator is used to generate an address signal based on the reference signal and a triggered scan input signal. Thus, a selector can select one key matrix code designated to the address signal from the mapping unit. Additionally, an interface converter further converts the selected key matrix code into a pair of differential signals compliant with the USB specification.

Abstract: A dual-function keyboard with two operational modes, a typing mode and a pointing mode. In the typing mode, each visible key functions as in a standard keyboard. In the pointing mode, all the keys function as pointer controllers. The keyboard also employs a novel “one-hot-encoding” circuitry that simplifies the wiring while allowing digital detection of any number of keys that are simultaneously depressed. The keyboard may be made of flexible materials and may be rolled-up or folded for easy transportation.

Abstract: An operation panel 30 is provided with a plurality of operation buttons 36. A string-like resistor body 41 is held in a resistor holding plate 31. The resistor body 41 has a tube-like elastic outer resistor member 42, an inner resistor member 43 loosely arranged within the outer resistor member and insulating spacers 44 arranged between the inner resistor member and the outer resistor member at predetermined intervals in the longitudinal direction of the inner resistor member so that the inner periphery of the outer resistor member 42 and outer periphery of the inner resistor member 43 are constantly separated from each other. A control unit 53 is provided to produce an operation signal.

Abstract: A method and system are provided for extending the functionality of application buttons on a limited resource computing device. Alternative application functions are launched based on the length of time an application button is pressed. A default function for an application is launched if the button is pressed for a short, i.e., normal, period of time. An alternative function of the application is launched if the button is pressed for a long, (e.g., at least one second), period of time. Still another function can be launched if the application button is pressed multiple times within a short period of time, e.g., double click.

Abstract: An antenna system for a radio frequency (“RF”) wireless keyboard includes a metallic plate as a part of the antenna system. The metallic plate is located within the wireless keyboard. A RF transmitter is coupled to the metallic plate and an antenna wire which form an the antenna loop. The antenna loop may also be directly integrated into the metallic plate by creating a cut-out space in the metallic plate. The antenna system may also include the metallic plate directly coupled with the RF transmitter so that the metallic plate is a whip or dipole antenna. The RF transmitter generates RF signals associated with particular keyswitches of the wireless keyboard. The antenna system transmits the generated RF signals to a RF receiver that resides separately from, and that communicates with, the wireless keyboard.

Abstract: A time-enhanced input device driver for a data processing system is capable of generating time-enhanced output in response to input signals. The input device driver receives a first input-event signal followed by a second input-event signal. In response to the second input-event signal, the input device driver generates a character code and an associated time-span code. The time-span code reflects the amount of time that separated the first input-event signal from the second. In an illustrative embodiment, the first and second input-event signals may comprise a key-down signal from a particular key on a keyboard and a key-up signal from that key respectively, in which case the generated character code would correspond to that key.

Abstract: Key patterns configured to accommodate the handicaps of the disabled user are imprinted or embossed on a sheet of conformable material. A matrix of sensing circuits for a keyboard are placed under the sheet to detect when and where the sheet is depressed and provides an output to a keyboard controller indicating which portion of the keyboard has been contacted. The keyboard controller relates the position data to the keyboard pattern on the sheet and provides key signals to the computer interface connector of the keyboard that are indistinguishable by a computer system from the QWERTY outputs of a standard keyboard. This enables the disabled user to carry this keyboard from one computer system to another and simply exchange it for the standard keyboard for the computer. Since the keyboard can be configured to accommodate the users handicap, no changes need be made to the operating system or any software of the computer in order to allow the disabled user to use the computer.

Abstract: An improved method and apparatus for scanning a keyboard matrix. A switch matrix having a plurality of rows and columns is operably connected to a wireless interface device for use with a wirelessly enabled host. Switch transition circuitry generates an output signal upon detection of a transition in the voltage level of at least one row in the switch matrix from a first state to a second state. Control circuitry latches the state of the columns and rows in the switch matrix upon detection of a voltage transition by the switch transition circuitry and scan logic scans the rows and columns of the switch matrix to detect operation of at least one switch in the switch matrix by testing the state of all columns latched in a high state. Control circuitry operating in cooperation with the scan logic and the driver logic change the state of the columns from a first state to a second state to detect the state of an associated row in the switch matrix.

Abstract: A key switch 102 formed by arranging a plurality of key contacts SW11, SW12, SW21, SW22,—at cross points of a key matrix is provided with a power supply control key (SW11), and a key scan circuit 101 for detecting open/close states of the plural key contacts of the key switch 102 is independently arranged from a power supply control key state detecting means for detecting the open/close state of the contact SW11 of the power supply control key. The depression of the power supply control key (SW11) is detected by the power supply control key state detecting means. When the operation is ended, or the power supply is turned OFF, the depression of the power supply control key is detected by the key scan circuit 101, and the supply of the electric power is stopped.

Abstract: Herein disclosed is a keyboard apparatus which comprises a plurality of keys each including a key holder, a scan board operative to input a key holder signal of each of the key-pushed actions of the keys, a memory for memorizing a key code relevant to the key holder, a plurality of numerical keys each having a key code inputted therein and outputting a key code signal indicative of the key-pushed actions of the numerical keys, a CPU having the key holder signal and the key code signal inputted therein, and state setting means for selectively setting two operation states respectively having the key holder signal and the key code signal outputted from the CPU.

Abstract: The present invention provides to low noise and attenuate electromagnetic interference with a matrix keyboard circuit that the total number of key depend on the multiplication of N and M, (wherein “N” equals to the quantity of column unit and “M” equals to the quantity of row unit) and the intersection of every row and column connect to switch by ground signal. Keyboard normally open that the truth table of matrix Keyboard is logic “1”. When keyboard actuate the key that make a short circuit for row circuit, column circuit and ground signal, the truth table of matrix keyboard is logic “0”. Because of processor read the row and column signal, it may decode the signal for identification of the actuated key. The present invention provides a matrix keyboard circuit for general low-cost matrix keyboard, which employs a no scanning pulse signal to develop a matrix keyboard of low noise and attenuate electromagnetic interference.