Abstract: A wireless input apparatus includes a transmitting section responsive to turning-on of a switch for transmitting a prescribed signal, and a transmission control section for measuring a time period during which an on state of the switch continues, and inhibiting the transmission by the transmitting section when the measured time period becomes equal to a prescribed time period.

Abstract: A character recognition mobile telephone registers and performs various functions of the telephone using a character recognition function. The character recognition mobile telephone includes a function character storage for registering character codes corresponding to various functions of the mobile telephone; a touch screen with which a user inputs a desired function character; a character recognizer for generating feature data for the character input from the touch screen and a corresponding character code, and searching the function character storage for a character code identical to the generated character code; and a controller for entering a function mode corresponding to the input character.

Abstract: A keyboard device incorporating a power supply checks whether or not the power supply is turned on. If it is, the device determines whether or not the device is connected to a cellular phone. If the connection is determined, the keyboard device is set to an active state and a light emitting diode (LED) in an LED portion is turned on to indicate the active state. If the keyboard device is not connected to the cellular phone, the device is set to a standby state. In this state, the keyboard device is in a mode where a connection state with respect to a cellular phone is monitored, without turning on the LED. The power dissipated in the power supply of the keyboard device is minimized, thus the device is capable of operating for a long period of time.

Abstract: A one-chip microcomputer system of the present invention, includes: a display driving circuit for driving a display device, a scanning circuit for outputting a key scanning signal to scan a keyboard switch; a common pert used for scanning the keyboard switch, and driving the display device; and a controller for controlling parallel processing of scanning the keyboard switch and driving the display device.

Abstract: The invention is related to a method and a device for use in an apparatus, preferably a portable radiotelephone, equipped with a number of keys. Upon activation of a key, the device detects which key has been activated. The device comprises a signal generating unit which generates an oscillating signal whose character, e.g. frequency, unambiguously corresponds to the activated key. A signal detecting unit determines from the character of the oscillating signal a digital value which unambiguously indicates which key has been activated. An advantage offered by the invention is that the device can be implemented by use of simpler and cheaper circuits than prior known devices of similar type.

Abstract: A programmable membrane switch input/output system is described. The system includes a membrane switch having a matrix layout embedded in a plastic film with a plurality of switches located at specific locations on the film. Output lines from the matrix layout are electrically connectable to a conversion unit which converts the output signals from a first code dependent on the matrix layout and the position of the switches to a second code which is independent of the position of the switches and the matrix layout. The conversion unit can convert the output signals into a serial code which can be transmitted serially from the conversion unit to a processing device located remotely from the membrane switch. By transferring the output signal serially from the conversion unit to the processing device, the cable can have fewer lines and less space is taken on the processing device for the connection.

Abstract: A combination keyboard and pointing device is incorporated in a portable computer and includes a dielectric base member on a top side of which a spaced series of electrically conductive pad member portions of a capacitance-based proximity sensing system are formed. Manually depressible key members are positioned above the pads. With the sensing system switched to a typing mode, the pads capacitively sense the proximity, velocity and acceleration of a user's fingers depressing their associated keys and output signals useable by the computer to display the character associated with the depressed key. A sensed increased stroke velocity of each manually depressed key may be used to alter the key character image displayed on the screen, for example capitalizing, bolding or underlining the character.

Abstract: A keyboard with a simplified structure, which is connected to a main computer having a microcomputer in which a key map is stored therein and which generates first and second scanning signals via respective scan input lines and receives first or second scanning codes via respective scan output lines upon a key on the keyboard being operated. The keyboard includes first and second keyboard frames separated from each other, and a first key matrix assigned to the first keyboard frame and disposed adjacent thereto, for generating the first scanning code in response to the first scanning signal, and a second key matrix assigned to the second keyboard frame and disposed adjacent thereto, for generating the second scanning code in response to the second scanning signal.

Abstract: A keyboard scan code snooper device comprises a microcontroller, a display, and an oscillator. The scan code snooper may be attached to the data and clock lines of a keyboard serial interface connecting a keyboard with a computer in a pass through configuration. The firmware in the microcontroller processes the snooped data transmission from the keyboard to the computer and vice versa, and generates signals appropriate to drive the display.

Abstract: A "Fn" key included in control keys is located adjacent to, for example, a first cursor movement key (for leftward movement) which is located on the right side of a space bar. A second cursor movement key (for rightward movement), a third cursor movement key (for upward movement) and a fourth cursor movement key (for downward movement) are arranged adjacent to the first cursor movement key. The arrangement of some data keys and control keys is adjusted so that the space bar can be situated in a predetermined position in the keyboard. When one of the first through fourth cursor movement keys is depressed with the Fn key depressed, a keyboard controller generates a key code with a control function corresponding to the combination of the depressed keys.

Abstract: A user input device is disclosed adapting the electronic components of a time-domain reflectometry material level sensor to replace traditional user input devices such as push-buttons, control knobs, and variable sliders. An electrical conductor is arrayed beneath an input panel, such that when a high permittivity or high conductivity material is placed in proximity to the conductor, the characteristic impedance of the conductor is altered at that point, reflecting electronic pulses transmitted through the conductor. The reflected electronic pulse is received by the associated electronics, and the position of the material along the conductor subsequently determined. By segmenting the conductor into virtual regions, each corresponding to an individual "button", discrete input may be received by the device based upon the placement of the material within specific virtual regions.

Abstract: A wireless keyboard or keypad (22) is powered remotely by a radio frequency exciter/receiver (20) and used in a radio frequency identification system (10). The wireless keyboard and the exciter/receiver communicate without wires via electrostatic or electromagnetic radiation. No power source is integrated with the wireless keypad. Thus, the wireless keypad is readily added to, or retrofit into, an existing radio frequency identification system. The keyboard has a plurality of keys (24) or control members that are manually actuated. Depression of a key or button, or other actuation of a control member, causes a predetermined response signal associated with that key to be generated. The response signal relates to an operation for a device or system associated with the exciter/receiver.

Abstract: In a keyboard with a restricted number of input keys, shifting between upper-case and lower-case character letters is effected with a key which is otherwise available for character or symbol entry. The upper case shift is accomplished by actuating a control element while observing a particular timing condition. Toggling the control element allows for comfortable caps shifting.

Abstract: An input detection circuit includes a matrix of keys formed by the intersection of a plurality of columns of keys and a plurality of rows of keys, with a crossover capacitor connected across the intersecting row and column of one of the keys. The input detection circuit further includes circuits for generating a difference in voltage potential across the capacitor, and circuits responsive to the difference in voltage potential across the capacitor for generating a signal representative of the presence of the capacitor. By knowing which keys have been connected with a crossover capacitor, the processor of the telephone will also know what scan options have been programmed.

Abstract: A keyboard for reducing the power consumption of the controller when scanning the keys in the key matrix and/or transmitting the key codes of operated keys. The operation mode of the keyboard is switched from the normal mode to the stop mode to stop the operation of the clock signal generator and the operation of the controller including the generation of a scan signal for the key matrix when all keys arranged in the key matrix are held in the key-off state for longer than a predetermined period of time, for example five seconds, after any of the keys has been operated or when any of the keys in the key matrix has been keyed on and held in the key-on state for longer than a predetermined period of time, for example 60 seconds.

Abstract: A secure keypad device incorporating measures to prohibit electronic eavesdropping. Random interrogation of the rows and/or columns of a keypad matrix is employed to determine which key has been pressed. Implementation of the random interrogation process utilizes the mathematical factorial (!) function in conjunction with an algorithm that derives an interrogation sequence. A random number is generated and fed to an algorithm which will derive an interrogation sequence. The sequence is relayed to a keypad scanner which performs the actual interrogation in order to determine which key has been pressed. Further measures are taken to guard against electronic eavesdropping. For instance, the algorithm is designed to take the same amount of time for an unsuccessful key scan as it does for a successful key scan. Also, the time spent on an unpressed scan line is approximately equal to the time required to record a valid key press.

Abstract: A method for forming a character string, an electronic communication device (31) and a charging unit (29) for charging the electronic communication device, wherein the communication device (31) does not comprise at all number/letter keys used for the selection of a phone number. The numbers or letters are selected from a display (39; 41) by means of selecting keys (32-38). The invention can be exploited, for example, in portable mobile phones.

Abstract: In an apparatus with a limited keypad (100, 300) several characters can be associated with each key. Characters associated with a key are determined on the basis of the language selected (200) as the operating language of the apparatus. The apparatus comprises a memory element (302) which includes a certain part (302a) for storing information indicating which set of the possible characters entered as push-button commands is in use as well as character set tables (302b-n) for selectively associating certain characters with each key on the basis of the information in said part (302a).

Abstract: The present invention comprises a cache based scan matrix keyboard controller system. The cache based scan matrix keyboard controller system includes a plurality of keys on a keyboard adapted to signal when a key is activated. The cache based scan matrix keyboard controller system also includes a cache memory component and a state machine. The cache memory component stores information regarding the keys for a period of time. The state machine is adapted to interpret the information in the cache memory component to efficiently control said keyboard in a manner that minimizes reliance on CPU processing and reduces expenditure of design, manufacturing and operating resources.

Abstract: A method and system for expanding the features and functions of a CD-ROM drive by facilitating communication between the drive and a host computer. The communication allows a user to control the basic functions, such as volume control, fast forwarding, and playing, from the hard buttons and knobs from the front panel of the drive without incurring conflict with the host computer. It can also allow an IRDA module to be attached to the drive to transfer IRDA data via the IDE/ATAPI port. A parameter and control pages are stored in the firmware of the CD-ROM drive. The parameter page provides parameters to define the input devices, and the control pages update the changes in the status of the input devices. The host computer reads the control pages at a predetermined interval and issues appropriate command based on the changes in the status.

Abstract: A method for transmitting key characters representative of keys on a keyboard is provided. A probability of use for one or more of the key characters may be determined by counting the number of occurrences of the key characters for a predetermined time period or for a literary work. Alternatively, the number of occurrences of one or more of the key characters may be calculated in real time and the probability of use adjusted accordingly for the key characters. Based on their calculated probability of use, the key characters are mapped into transmission formats. A system and a keyboard are also disclosed which map key characters into transmission formats based on probability of use of the key characters. Additional methods are disclosed for using error detection data in the transmission formats. Exemplary error detection may include adding parity bits or configuring the data in the transmission formats to indicate errors.

Abstract: A method and an interface circuit for scanning keys and external resistors of a keypad are disclosed.

Abstract: A multimedia keyboard structure which includes a standard keyboard having a control key pad having a set of keys for cursor, number, screen scroll and multimedia function controls. The control key pad is connected to the scan matrix formed by the I/O lines of the microprocessor of the internal circuit structure of the keyboard. The scan code of Num Lock or Scroll Lock is adapted to match Win 95's register in testing the flag bit of Num Lock or Scroll Lock and judging its flag bit through a driver so that the job of code converting can be executed. The operator is allowed to directly control the control key pad and to monitor the operation through a display screen to which the standard keyboard is connected by means of employing the function provided by WindExec O of Windows API to the path of the file and the file index of the application program.

Abstract: This invention relates to a keyboard with additional hot keys which can be used to control and manipulate peripheral equipment, for example, a multi-media peripheral equipment. It generally comprises a keyboard and a plurality of, namely 1 to 15, hot keys disposed at said keyboard. Said hot keys are interconnected to the I/O ports of the circuit configuration of the micro processor of the keyboard, accordingly, a new 9.times.16 scan matrix is transformed from original 8.times.16 scan matrix. Those hot keys can be executed according to the application program of the Windows. By this arrangement the operator may directly control and manipulate the multi-media peripheral equipment and the status can be displayed on the monitor directly as well. Besides, those hot keys may also be designed with a macro procedure to carry out preset controlling procedure, i.e. filecopy, or other function.

Abstract: A radio telephone has an array of manually operable switches mounted on a respective support. A processing circuit processes signals received via said switches and said support supplies signals to said processing device over a single transmission line. The processing device is arranged to determine an analogue characteristic of a signal received from the support via said transmission line in order to determine which of said manually operable keys has been manually operated. An analogue-to-digital converter can be used to measure voltage values identifying key selection or a timer can be used to measure capacitor charging or discharging.

Abstract: A mobile telephone includes a memory (11) in which both a telephone number and an associated name can be stored. The telephone includes a visual display (8) and a keypad (9) with a plurality of keys (9a) each having a number and several (eg three) alphabet characters associated therewith. In a first data entry mode a telephone number may be entered into the memory (11) by pressing the respective numeric keys (9a) once in turn. In a second data entry mode a name may be entered and appended to the telephone number by pressing the relevant key (9a) an appropriate number of times. For each key one key press displays the first letter, two key presses displays the second letter, and three key presses displays the third letter associated with that key. In a data retrieval mode, however, a data item to be searched is entered by pressing only once for each character the respective keys (9a) having the desired character associated therewith.

Abstract: An information processing apparatus is capable of using more than one type of keyboard with a single keyboard controller without increasing the production cost. In a keyboard matrix, a key scanning line C0 is arranged so that the key scanning line C0 is only connected to any one of key return lines R0 to R7 through a key switch having a key switch number G01. The key switch number G01 is assigned for the key [F1] which is common to keyboards having different key arrangements. When the information processing apparatus is activated, a keyboard initializing program is activated by depressing the [F1] key. As a result, the information processing apparatus identifies the type of the keyboard by detecting a key return line R from which a signal is returned when scanning is made upon the depression of the [F1] key.

Abstract: A microcomputer has an output port and an input port. A plurality of switches are provided between and matrix-connected to respective bits of the output port and respective bits of the input port. The microcomputer renders all of the bits of the output port in an output state, and in this state, checks whether an output of the output port is obtained at one of the bits of the input port. When an output of the output port is obtained at one of the bits of the input port, data indicating a manipulated one of the plurality of switches is acquired by rendering, in order, the bits of the output port in an output state, and then the process of acquiring data indicating a manipulated switch is again executed after a lapse of a predetermined amount of time. The acquired data is made effective if a first acquired data and a second acquired data are identical.

Abstract: An apparatus and method for recovering "break" codes transmitted by a keyboard that are not properly received by the receiver of the computer system. The keyboard is an infrared keyboard that transmits to a receiver in the computer system "make" codes when the keys are depressed and transmits to the receiver "break" codes when the keys are released. Upon receipt of the "make" and "break" codes, the receiver keeps track of the status of each of the keys, i.e., depressed or released, by updating a database in response to receipt of the "make" and "break" codes. At select time intervals, the keyboard transmits to the receiver an "idle" code containing data corresponding to the status of each key. Upon receipt of the "idle" code, the receiver compares the "idle" code with the status of each key as indicated by the data base. The receiver then generates a "break" code for each of the keys that do not compare.

Abstract: An interactively illuminating computer input device for a computer is disclosed. In one embodiment the device is a keyboard. The keyboard has a bi-directional communication link between the keyboard and the computer. The keyboard also has one or more keys, each capable of illumination. The keyboard also has a keyboard controller, operably coupled to the bi-directional communication link and the keys. The keyboard controller detects depression of a key on the keyboard by the user of the computer. The keyboard controller also controls the illumination of a key on the keyboard by the computer. In one embodiment, the keyboard controller receives from the computer a unique command for each key to illuminate the key. In a further embodiment, the keyboard controller receives from the computer a unique command for each key to dim the key.

Abstract: A touch sensor switch that responds to touching, or even to the proximity of an object, is disclosed. The switch includes a number of capacitance elements, or touch pads, that produce an effective capacitance dependent upon the physical proximity of the object. A microcontroller under control of a program stored in a read-only memory causes its I/O port to set a transient voltage on each capacitance element as a logic level. Each transient voltage is at variance with the capacitive element's preferred voltage level. The program then reads the I/O port, and hence the logic levels of the capacitance elements, as the capacitive elements revert to their preferred voltage levels, and calculates the proximity of the object, or touching, from relationships among recorded signals. The circuit may also be embodied in an application specific integrated circuit.

Abstract: An ADC (analog digital converter) keypad apparatus controls key inputs according to a voltage divided by a plurality of voltage dividing resistors. The ADC keypad apparatus includes an ADC keypad, an A/D converter for converting a divided voltage which is determined according to a key input, a memory for storing key discriminating data, a display for displaying status information, and a controller for re-establishing the key discriminating data. Upon receiving a key re-establishing signal from the A/D converter due to a change of the divided voltage, the controller provides the display with a display signal for displaying the status information and re-establishes the key discriminating data.

Abstract: An input apparatus capable of controlling a plurality of electronic devices including a set-top box includes comprises: a first operation key part having a plurality of operation keys; a second operation key part having a plurality of operation keys; a control key part having at least one control key; a control unit for generating operation information for a first electronic device when any operation key of the first operation key part is operated, the control unit further generating operation information for the first electronic device when, with no control key of the control key part operated, any operation key of the second operation key part is operated, the control unit further generating operation information for a second electronic device when, with any control key of the control key part operated, any operation key of the second operation key part is operated; and a transmission unit for transmitting the operation information generated by the control unit.

Abstract: A switch array decoding circuit, suitable for use in a keyboard, and method according to the present invention comprises a matrix of row lines and column lines. Switches from the array are connected between intersections of the row lines and column lines. The row lines and column lines are connected to I/O pins leading to one or more components containing the decoder circuitry. The decoder circuitry first simultaneously drives the row lines while sensing the column lines. When a switch closure is detected, the states of all column lines are simultaneously sensed. This operation determines the column position(s) of the one or more switches being closed. The column lines are then simultaneously driven while simultaneously sensing the row lines. This operation determines the row position(s) of the one or more switches being closed. The row and column drive and sense order may be reversed.

Abstract: An electronic device (100) includes at least L keys (114) and a processor (506) having at least M inputs (600). Upon actuation, each one of the at least L keys (114) toggles a unique combination of N inputs of the at least M inputs (600), where each unique combination is taken from all possible combinations thereof. The at least M inputs (600) are read by the processor (506) and compared to a plurality of predetermined key patterns (806). Upon a match between the at least M inputs (600) and one of the plurality of predetermined key patterns (806), a key actuation is detected and a predetermined function may be processed in response thereto. The processor (506) may ignore simultaneous key actuations where combinations of inputs greater than N are toggled.

Abstract: A key scanning circuit scans a key matrix circuit to generate key input data as for key operations. A remote control decoder decodes an encoded signal, which has been output from a remote control transmitter and received by a remote control receiving circuit, to generate remote control data. A transmission register selectively stores either the key input data or remote control data. By transmitting the data stored in the single transmission register, it is possible to transmit any one of the key input data and remote control data to the microcomputer.

Abstract: In a keyboard arrangement and method for identifying a pressed key according to the present invention, conductor lines (4', 6') at each key (B), which may be connected together, are connected to a ground plane (24, 23, 27) as a response to a pressing (P) of a key. The pressed key (B) is identified by detecting the conductor lines that are connected to the ground plane. All the conductor lines may be connected as pulled-up inputs of a detector circuit, and any conductor line or combination of conductor lines may be used to identify a key. A noticeably greater number of keys may be simply identified with the same number of conductor lines than is possible in a solution according to the prior art. In an advantageous embodiment of the present invention, the means for connecting the conductor lines (4', 5', 6', 7') to the ground plane (27) is a conductive plate (23), which essentially covers the whole keyboard. This also provides a good shield against electrostatic discharges and other interference.

Abstract: A data entry system (100, 100') has an ergonomic base (102, 102') including upper surface controls (104, 104') which generate a first set of electrical signals, and side surface controls (106, 106') which generate a second set of electrical signals when operated independently. A third set of electrical signals are generated when the side surface controls (106, 106') are operated in combination with the upper surface controls (104, 104'). Data entry system (100, 100') further includes mode selection controls (108) for establishing the first, second and third sets of electrical signals as device control signals responsive to a first mode being selected and respective sets of alphanumeric and keyboard control signals responsive to a second mode being selected.

Abstract: Driving circuitry for a switch matrix provides a reset voltage to all rows of the matrix in between scans to recharge switch capacitance. Column detection circuitry is disabled in between scans so that column driving circuitry may also `reset` the charge on capacitors reducing the scan time and/or allowing a greater number of switch elements, element size, or EMI suppressing capacitances. Pull-up resistors are supplemented or eliminated through the use of active current sourcing and sinking for the drivers.

Abstract: A wire/wireless keyboard and a control method therefor. The keyboard can be used as a wire keyboard if a main body connecting section of the keyboard is connected to a computer body, and the keyboard can be used as a wireless keyboard if the main body connecting section of the keyboard is disconnected from the computer body. The connection status between the computer body and the main body connecting section of the keyboard is automatically judged. If it is judged that they are connected, then the power of the computer body is selected, and the wire mode is executed. On the other hand, if it is judged that they are disconnected from each other, then the internal battery is selected to supply the power from the battery, and the wireless mode is executed. Therefore, the keyboard can be used as both a wire keyboard and as a wireless keyboard.

Abstract: A keyboard for lowering the power consumption for key code transmission and enhancing the reliability in code transmission. When key codes corresponding to an operated key in the laid out keys are transmitted to a signal processing unit, a status code indicating whether a function key (Shift, Control or Alt key) has been operated is also transmitted at the same time, transmitting no key-on repeat code that is obtained when one key is operated continuously as with a conventional keyboard.

Abstract: A keyboard matrix of a keyboard has drive lines including a set of lines to be selectively activated for detection of depressed keys and scan lines including a set of lines to be selectively monitored for detection of depressed keys. The keyboard matrix includes circuitry for connecting one of the drive lines with one of the scan lines for providing an identification of the keyboard.

Abstract: A method and apparatus for improved scanning keyboard and diodes option is disclosed. Each of the pins is treated as one independent dimension so as to define a multi-dimensional configuration. The circuit includes a clock generation circuit, a keyboard I/O port device comprising a plurality of ports associated with the pins and a key detection register device. A key is arranged at the interconnection of any two ports. When the key is depressed, by maintaining the ports at a first level and applying a second level to each of the ports to check which port goes from the first level to the second level, the location of the key may be determined. The output of the ports are stored in the key detection register device for the determination of the key location.

Abstract: A cover-actuated keyboard encoding system is disclosed which can be used either alone or as a part of a universal remote control unit. It contains (a) a keyboard; (b) a memory for storing a plurality of control codes; (c) a special keyboard cover for covering the first keyboard; and (d) a computer program to convert the covered keys of the first keyboard into a control code. The keyboard cover is designed such that it contains one or more key-seat protrusions which are arranged such that they will be pressing against one or more of the first keys when the keyboard cover is closed. A CPU is programmed to scan the key board and convert the scanned keyboard value to a control code, in accordance with the number and locations of the keys that are being pressed during a power-on or a reset.

Abstract: An arrangement for providing key switch actuation detection which reduces the number of key switch inputs required at a key switch controller. A key scanning system for detecting the activation of keys on a key-based input device is provided, having a plurality of logic level sensors to detect and temporarily store logic levels on corresponding connection nodes. A plurality of switches, each coupled to one of the keys, provides a pattern of logic levels on the connection nodes in response to the activation of a particular key. A logic monitor is coupled to the logic level sensors to detect the stored logic levels and recognize the activation of the particular key based on the pattern of the stored logic levels. A method for performing key switch actuation detection that reduces the number of required key switch inputs is also provided.

Abstract: Apparatus to provide security for a keypad processor of a transaction terminal includes a secured processor coupled to a keypad and processor of the transaction terminal. The apparatus may operate in a secured or an unsecured mode. In a secured mode, the apparatus prevents the fraudulent acquisition of information, such as personal identification numbers (PIN), entered through the keypad. By encrypting data entered through the keypad, the apparatus prevents the fraudulent acquisition of information transmitted to a processor such as a central computer of a bank. The secured processor provides actual and false sampling of the keypad and simulates keypad data entries to prevent an electronic eavesdropper from determining the actual keypad entries.

Abstract: An ergonomic keyboard utilizing ten keys which are activated in pairs to produced coding signal representing alphabetic symbols of a conventional computer keyboard. The keyboard is operated as a replacement or in parallel with a conventional computer keyboard. Each key corresponds in position with each finger on a hand. By pressing two keys, unique letters and functions are produced. As the number of unique binary combinations of ten elements is 45, the ten-key keyboard system is capable of representing at least 26 characters plus the function keys of a standard 101-key computer keyboard. The structure enables greater speed through efficiency in finger movement and easy learning.

Abstract: An apparatus and method for scanning a triangular or trapezoidal key matrix for data input by depressing keys of a keypad. The key matrix allows an increased number of keyswitches to be provided on the key matrix while reducing the number of I/O ports on the I/O interface. The apparatus includes an I/O interface connecting the keypad to the CPU. The keypad I/O interface is provided with m I/O ports, where m is plural integer. Through detecting the voltage levels of these I/O ports, the CPU is able to determine which key on the keypad is being depressed. A triangular key matrix is constructed with a set of m code lines and at least one auxiliary code line arranged in such a way as to form a triangular array of m.times.(m+1)/2 cross-points. Each cross-point is provided with a keyswitch associated with a key on the keypad. The m code lines are connected correspondingly to the m I/O ports on the keypad I/O interface.

Abstract: An electronic device (100) comprises a first plurality of keys (117), a second plurality of keys (119), and a processor (506) having a plurality of inputs (600) and an output (620). The output (620) is utilized to bias the plurality of inputs (600) at a first predetermined voltage during a first predetermined time period and at a second predetermined voltage during a second predetermined time period. An actuation of any one of the first plurality of keys (117) couples a unique combination of two inputs of the plurality of inputs (600) to the second predetermined voltage, and an actuation of any one of the second plurality of keys (119) couples a unique combination of two inputs of the plurality of inputs (600) to the first predetermined voltage. Thus, the processor (506) can detect actuations of the first plurality of keys (117) during the first predetermined time period and the second plurality of keys (119) during the second predetermined time period.

Abstract: An apparatus and method for scanning a triangular or trapezoidal key matrix for data input by depressing keys of a keypad. The key matrix allows an increased number of keyswitches to be provided on the key matrix while reducing the number of I/O ports on the I/O interface. The apparatus includes an I/O interface connecting the keypad to the CPU. The keypad I/O interface is provided with m I/O ports, where m is plural integer. Through detecting the voltage levels of these I/O ports, the CPU is able to determine which key on the keypad is being depressed. A triangular key matrix is constructed with a set of m code lines and at least one auxiliary code line arranged in such a way as to form a triangular array of m.times.(m+1)/2 cross-points. Each cross-point is provided with a keyswitch associated with a key on the keypad. The m code lines are connected correspondingly to the m I/O ports on the keypad I/O interface.