Electrical computers and digital data processing systems: input/ – Input/output data processing – Input/output access regulation
Reexamination Certificate
1998-11-23
2001-07-17
Lee, Thomas (Department: 2182)
Electrical computers and digital data processing systems: input/
Input/output data processing
Input/output access regulation
C710S031000, C710S062000, C710S067000, C709S218000, C235S462010, C235S472010
Reexamination Certificate
active
06263383
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to the field of keyboard wedge systems and processing of data streams, and more particularly to simplified configuration of barcode symbol scanning systems and processing of data streams therefrom.
2. Description of the Related Art
Barcode scanning systems have found an ever-increasing number of uses and applications. For example, barcoding has been utilized for inventory and warehousing applications, as well as with point of sale terminals. Many different types and complexities of barcodes systems have been used. A typical basic barcode symbol scanning system includes a barcode scanner, a decoder and a computer. The scanner and decoder have been utilized to retrieve information from barcodes for use by the computer system.
Conventional linear or one-dimensional barcodes have been in use since about 1970. The usefulness of such barcodes is limited by relatively small data capacity. To overcome this limitation, two-dimensional barcode symbologies have evolved. These symbologies are capable of encoding large amounts of data. For example, PDF417 barcode can encode up to 1800 ASCII characters or 2700 digits. However, in some applications only a portion of the scanned information is needed.
As part of a barcode reading system, a decoder is defined as an electronic package that receives a signal from the scanner, interprets the signal into meaningful data, and provides the data to other devices of the system. So far as known, there are three main types of decoders: wedge decoders, serial decoders and software decoders. Wedge decoders are systems that provide a decoding function for computer input. With keyboard wedge decoders, the data is decoded so that it appears as though it was manually typed or keyed directly into the computer. The basic function of keyboard wedge devices is conversion of scanned data into codes that are like those of keystrokes or keyboard data. Some keyboard wedge devices also have capability like that of software decoders to manipulate the scanned data, adding characters to the data stream or remapping the data stream altogether. However, to enable this data manipulation capability, the scanner must be manually pre-configured by scanning a multitude of special types of bar codes. This is a very complicated and time-consuming procedure.
Serial decoders are also external devices that connect into a communications or COM port of the personal computer. Typically, decoded scanners (i.e., scanners in which the decoder is integrated, usually into the handle of the scanner) are expensive.
Software wedges, located within the PC software, received the scanner data generally via the COM port. The received scanner data is then re-routed within the computer to the keyboard buffer. The data thus appears to other parts of the computer to have originated from the keyboard.
Many different types of scanning devices have been available. Scanning devices include wands, charge coupled device (CCD) scanners and laser scanners. Wand scanners tend to be the least expensive, followed by CCD scanners and laser scanners (the most expensive). Most scanning devices use a light emitting diode (LED) and a photo detector to scan barcodes. The light generated from the LED falls on the barcodes and is absorbed by the printed bars and reflected by the white spaces. The photodetector senses the reflected light and electro-optically converts the reflected light into a signal. The digitized signal is then sent to a decoder and converted into ASCII or other types of data characters.
Currently, there are more than 400 barcode symbologies in use. Each character in a barcode symbology is generally represented by a barcode in the form of a series of bars and spaces. Typically, each barcode symbol, as encoded, includes a quiet zone, start code or pattern, data characters, stop code and trailing quiet zone. Many symbologies support a check digit or digits to ensure data integrity. With such symbologies, the check digit or digits are usually located before the stop code. A barcode symbol is represented by a combination of barcode characters including the start/stop codes, quiet zones, data characters and check characters (as required by a particular symbology) that forms a complete, scannable entity.
SUMMARY OF THE INVENTION
Briefly a scanning system according to the preferred embodiment of the invention utilizes a decoded keyboard wedged device together with a keyboard hook device for system configuration and data manipulation. The keyboard wedge functions to accept data read from a barcode scanner and pass the data to a computer system as normal keyboard typed keystrokes. Thus, the keyboard wedge of the present invention converts data read by a scanner connected to a computer input into a format like that of data from the computer keyboard. The scanner data thus appears as though it were from the keyboard, allowing scanned data transmission over a standard keyboard line. The keyboard hook functions to intercept the data passed from the keyboard wedge to the computer. A processing application then can process the data passing through the keyboard hook. The processed data can then be sent to the computer for use in the desired application.
In operation, the scanning system of the present invention allows typed keystrokes from the keyboard to pass through the keyboard hook directly to the computer while the scanned data keystrokes are routed from the keyboard hook to the processing software. Thus, the keyboard hook provides a window to the keyboard data line, through which the processing software can distinguish typed from scanned keystrokes. Since only scanned data is processed, normal keyboard operation is not affected and system resources are conserved.
The processing software utilizes the keyboard hook to provide a number of data manipulation functions, including adding and clipping data characters, special formatting and parsing of data components. Furthermore, since the keyboard hook provides a path off of and onto the standard keyboard line, the processing software allows a user to selectively pass only those portions of data or formats thereof that are appropriate for a particular application. Further, because the processing is performed in software, the system can be easily configured to accept different scanned data decode formats without the need for different or additional system hardware.
In addition, the scanning system of the present invention provides an improved method of configuring the processing software. The processing software is configured to recognize what the scanned keystrokes look like. Scanned data is thus reliably detected and routed to the processing software while typed keystrokes are passed directly to the computer. Auto-configuration is achieved by supplying expected characteristics of the scanned data to the software, including average time between keystrokes and a minimum number of keystrokes over which average time is maintained. These characteristics represent threshold values that are used to test incoming keystrokes. Simplified configuration may also be achieved using a preamble/postamble protocol. In this mode, the software inspects data passing through the keyboard hook for special known characters which precede and follow the scanned data packet. Using either of the configuration modes, the present invention thus overcomes the need for time-consuming and complex manual scanner configuration.
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TAL Technologies, “Interpreting Serial Data,” last modified Feb. 06, 1998, Copyright 1997, pp. 1-4, http://www
Colburn Roger J.
Lee Glenn W.
Robertson Brent G.
Lee Thomas
Peyton Tammara
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