System for enabling decoding of bar code and other symbols with a digital microcomputer connected via the input/output port thereof to the scanner

摘要

A scanner communicates with a microcomputer over a serial communications link utilizing the serial I/O port of the microcomputer. Both signals representing the data which is scanned and signals representing commands to the scanner and commands from the scanner indicative of the status thereof (e.g., scanner trigger actuation) are communicated over a plurality of lines in the communication link. These lines may be of the type utilized for transmission of data and commands in accordance with a communications protocol, such as the RS-232 protocol. Interrupts are generated when the scanner is connected to the serial port via the communication link and the microcomputer is available for decoding. Then appropriate interrupts are generated to actuate the scanner and to respond to the data. The scanner may be a laser or optical beam scanner or a wand which is moved across a bar code symbol. The symbol has bars which are relatively opaque and reflective (black or white). The microcomputer translates the data which represents the width of each bar and the number of bars and the detection of the end of a bar code symbol (Quiet Zone) into digital values which are stored in memory and presented for decoding in accordance with programming of the microcomputer which decodes the symbol. The decoded symbol may be displayed graphically, with its opaque and reflective bars and the alphanumerics which the symbol represents, on the screen of a terminal including the microcomputer.