Abstract: An apparatus for reading a bar code symbol is provide which includes a bar code scanner and a receiver. The scanner transmits an RF signal representation of the bar code symbol to the receiver that includes substantially less information than that originally present in the bar code, thus reducing the need for electrical power. The receiver reconstructs the original information of the bar code symbol from the RF signal. The scanner comprises an encoding element that converts a first signal representative of light reflected from the bar code symbol to a second signal representative only of bar-to-space and space-to-bar transitions of the bar code symbol. An RF transmitter within the scanner provides an RF signal from the second signal. The receiver comprises an RF receiving element adapted to receive the RF signal and reconstruct the first signal from the RF signal.

Abstract: A system and method for dynamically adjusting operating parameters of a printer using bar code images to achieve optimal print quality. A reader operates in conjunction with a bar code printer and scans the output images printed by the printer. A verifier analyzes the scanned image to determine the quality of the output image. The system adjusts printer operating parameters, such as print speed, print head pressure, and burn duration to optimize the quality of the output image for a selected quality grade of output image. Adjustments are made in a closed-loop fashion without the need for user intervention.

Abstract: A brake apparatus for a printer is provided which rapidly decelerates and stops a rotating roll of print media in between printing operations, and allows the roll to rotate freely during printing operations. The printer includes a print head mechanism that draws a print media to a print region from a roll of the print media. A roller supports the roll of print media and permits the roll to rotate freely upon application of a drawing force from the print head mechanism. A brake drum is axially coupled to the roller. A lever arm is affixed at a first end thereof to a support structure of the printer and is pivotal between a first position and a second position. A second end of the lever arm has a pedal disposed at a portion of a path along which the print media follows toward the print region.

Abstract: A method for converting characters represented by a 16-bit character encoding standard or a numeric string into bar code symbols computes three values for the 16-bit code or numeric string. These three values are encoded into three bar code codes. Counts associated with the bar code codes are retrieved, along with character font data. Both the bar code symbols and the human-readable characters are printed on a bar code label. The printing apparatus includes a central processing unit for performing the above method, intercoupled with a bar code printer, memory, and secondary storage. A bar code reader similarly includes a central processing unit intercoupled with memory, secondary storage, and a bar code reader. This bar code reader scans the bar code symbols and decodes them into standard bar code codes. Groups of three codes are converted into three numeric values. The hexadecimal equivalent of these three numeric values is computed.

Abstract: A sealable, latchable door assembly for use with a hand-held, portable electronic device that has a housing adapted to removably receive a memory card in a receiving chamber through an opening. The door assembly includes a door shaped and sized to removably cover and seal the opening in the housing to retain and protect the memory card. The door has an engaging face adapted to sealably engage the housing around the opening. A connecting member attached to the door is slidably mounted within the housing to allow the door assembly to be slid between an extended, disengaged position and a retracted position with the door in a closed, sealed position. A latch attached to the door is adapted to releasably engage the housing to secure the door in the closed, sealed position. A hinge connected between the door and the connecting member enables the door to be pivoted downward to an open position to allow uninhibited passage of the memory card through the opening in the housing.

Abstract: A method and apparatus for error correction enhancement for machine-readable symbols applies particularly to symbols having symbol characters, repeating characters such as pad characters, and error correction characters derived from the symbol and pad characters. The method and apparatus read a selected symbol where the selected symbol has at least one damaged pad character. After failing to decode the symbol, the method determines that the symbol has at least one damaged pad character and then locates at least two consecutive pad characters in the selected symbol. The method replaces any damaged pad characters, and then again attempts to decode the symbol, using the error correction characters, after the pad characters have been replaced.

Abstract: A method and apparatus for calibrating a bar code scanner. The bar code scanner contains circuitry including a programmable read-only memory (PROM) which stores data affecting the operation of other circuitry in the bar code scanner. The operation of the bar code scanner can be optimized by being monitored by an adjustment circuit under the control of a computer, the adjustment circuit producing signals which change the data stored in the PROM. Among the aspects of the bar code scanner which can be affected are optimization of the output signal, optimization of the signal which causes the bar code symbol to be illuminated, and response of the bar code scanner to the lack of a bar code symbol to read.

Abstract: An optical element for causing a visible spotter beam emitted by a hand-held scanning bar code reader provides visible indications of the area of a surface which is being scanned by an invisible scanning beam. The optical element transforms the visible spotter beam, at its extreme of travel, into two pairs of cursor beams which are directed along predetermined trajectories relative to the trajectory followed by the scanning beam. The predetermined trajectories can be above and below, or to the left and right of the center of travel of the invisible scanning beam. In one embodiment, a method of identifying the proper focusing distance of the scanning reader is presented. The method identifies the focusing distance by making the pairs of cursor beams formed from the visible beam at its two angular extreme of travel to form a predetermined pattern indicating the proper focusing distance.

Abstract: A method of supplying an energization signal to a selected element in an array of print elements. Printing activity of the selected element and neighboring elements is determined, compressed and stored to memory. Based on the stored compressed printing activity data, an energization schedule for the selected element is determined using a look-up table technique. The data in the look-up table may also be compressed reducing the memory required by the energization data. Further reductions in memory are achieved by grouping portions of the printing activity data to identify common energization schedules for differing printing activities. The printing activity data may relate to temporal distributions and/or spatial distributions of printing activity of elements in the array. The method may be applied to linear or two-dimensional arrays of print elements.

Abstract: A method and apparatus for processing the information in a sequence of bar code symbols. The information contained in one symbol can be decoded and processed while the information in the next symbol is being gathered. A pulse width counter, under control of a microprocessor, accumulates counts representing the widths of the elements of a bar code symbol and the accumulated counts are latched into a separate latch buffer which is then transferred into the microprocessor memory by a direct memory access controller. A program in the microprocessor operates on the information stored in the microprocessor memory to decode, process and output the data and/or commands contained within a given symbol as the pulse width counter is accumulating the counts that represent the next symbol to be read. If the input device is an automated scanner, the scanner's Start-of-Scan signal is used by the microprocessor to specify the beginning and end of each scan.

Abstract: A symbology reader which reduces the effects of specular reflection. A plurality of illumination sources emit light toward a target object. A first polarization filter receives the unpolarized light from the illumination sources and transmits only light polarized in a first direction. Light reflected from the target object travels back to the reader where it is received by a second polarizer which is oriented to block light polarized in the first direction and transmit only light polarized in a second direction orthogonal to the first polarization direction. Non-specularly reflected light reflected from the target object is largely transmitted by the second polarizer to a detector assembly within the symbology reader. In one embodiment the polarization filters are part of a window which covers an output aperture of the reader. The polarization filters are implemented as discrete pieces of laminar polarizing film attached to a transparent window base.

Abstract: A method and apparatus for decoding profiles which fail to resolve narrow elements in symbologies employing one element type having only a single width, first begins by producing a series of counts from the symbol using standard waveshaping and counting circuitry. Second, an X-dimension for the 1-wide elements is determined based on the first few counts corresponding to bars after the counts corresponding to the quiet zone. The Start and Stop characters are located and the method determines whether the symbol is in focus. If the symbol is out-of-focus, then groups of an odd number of 1-wide elements are converted to large counts that correspond to pseudo elements (e.g., wide bars in a symbology containing only 1-wide narrow bars). The method groups counts into individual characters, and divides all pseudo elements into individual 1-wide elements. The method thereafter decodes the symbol.

Abstract: A two-dimensional matrix symbology reader comprises a fixed housing having a slot disposed in a side of the housing to receive a card medium having a two-dimensional matrix symbology affixed thereto. The matrix symbology is illuminated within the housing once the medium has reached maximum axial extent of the slot. An aperture is disposed within the housing adjacent to the slot relative to the matrix symbology such that the light reflected from the matrix symbology is transmitted therethrough. The reflected light is then converted to information signals representative of the matrix symbology. Due to the controlled environment and uniform depth of field requirement within the housing, a pin hole aperture or lens can be utilized without the need for additional focusing or aperture control.

Abstract: A method and apparatus for decoding profiles which fail to resolve narrow elements in complex multi-width symbols, first begins by identifying which elements in the profile are resolved. Second, the environments surrounding each resolved element are examined. Third, several closure boundaries are determined, and the widths of resolved elements are determined at a selected threshold. The size of each resolved element is determined based on its measured width at a threshold selected based on the environment surrounding the resolved element. Fourth, the distances between the centers of the resolved elements are determined. Thereafter, an X-dimension is determined for 1-wide narrow elements unresolved in the profile. Based on the X-dimension and known center distances, a matrix is constructed for determining the number of narrow elements unresolved between two resolved elements.

Abstract: A high cycle life switch assembly having a seal positioned between a trigger and a non-tactile switch with a snap dome positioned exterior of the seal and engaged by the trigger to give a high tactile feedback. The snap dome is mounted on the trigger and an actuator rod extends between the snap dome and the switch, through the seal, to apply an actuation force to the switch when the trigger is moved toward an actuating position. The actuator rod extends through an aperture in the seal and is slidably and sealably disposed therein to apply no force on the seal as the actuator rod is moved to actuate the switch located behind the seal.

Abstract: A symbology reader employing an area detector and LEDs mounted at various angular orientations on a printed circuit board for illuminating a target object in an object plane. Each of the LEDs is oriented according to a desired beam vector to illuminate a particular area of the object plane so that the sum of the beams produces a desired illumination pattern. In one embodiment, the illumination pattern is selected to be inversely proportional to the sensitivity of the area detector to provide an even response over an entire image area. The individual LEDs are angularly aligned by an alignment board having an alignment aperture for each LED. The LEDs are mounted onto the printed circuit board with their body portions spaced apart from the board and supported by semi-rigid wire leads soldered to the board. Each of the alignment holes of the alignment board is laterally offset slightly from the mounting position of the LED.

Abstract: A method and apparatus for detecting the presence of a surface which may bear a bar code symbol. The apparatus generates a series of pulses having a duty cycle which depends upon whether light reflected from a surface bearing a bar code symbol has been detected recently. If such a surface has been detected, the duty cycle is maintained at a high rate. Otherwise, the duty cycle is reduced substantially until such a surface is again detected to save battery power.

Abstract: A homodyne radio system for receiving direct sequence spread spectrum communications enables a received signal to be down-converted directly to a baseband signal. An input RF amplifier receives and amplifies a carrier signal modulated by a digital code sequence. A local oscillator provides a signal having a frequency substantially equal to the frequency of the carrier signal. A phase splitter coupled to the input RF amplifier receives the modulated carrier signal, and splits the signal into corresponding quadrature component signals. The mixer combines a first one of the quadrature component signals with the local oscillator signal to generate a first quadrature baseband output signal. A second one of the quadrature component signals is combined with the local oscillator signal shifted in phase by 90.degree. to generate a second quadrature baseband output signal.

Abstract: A system and method for the automatic selection printer operating parameters using a preprinted bar code image on a portion of a selected print medium or a separate sheet of bar code parameters and commands. The bar code image specified characteristics of the selected print medium. A bar code scanner operates in conjunction with a bar code printer and scans the bar code image. The system automatically selects printer operating parameters, such as print speed, print head pressure, and burn duration to configure the printer for optimal operation with the selected print medium. The bar codes can also be used for test and service, label design, data entry, or work in process.

Abstract: A method and apparatus for decoding profiles which fail to resolve narrow elements in multi-width symbols, first begins by identifying which elements in the profile are resolved. Second, the distances between the centers of the resolved elements are determined. Third, closure boundaries are determined, and the widths of resolved elements are determined at the closure boundary. The type of resolved element is determined based on its measured width. Thereafter, a unit distance is determined for 1-wide narrow elements unresolved in the profile. Based on the unit distance and the width of two adjacent resolved elements, a matrix is constructed for determining the number of narrow elements unresolved between two resolved elements. Based on the measured center distances, the resolved element widths and the matrix, all of the unresolved narrow elements are identified in the profile and the profile is subsequently decoded.