The Auto ID Book: Decoders
A decoder performs the translation of bar and spaces into ASCII characters. A bar code is decoded by using an external decoder, a software decoder, or a built-in decoder in the handle of a decoded scanner. An external decoder is a stand alone unit which is generally keyboard wedged between the keyboard and terminal. An external decoder can also be connected to the serial port of the computer. If the decoder is keyboard wedged, data appears on the screen as if it were typed directly into the computer.
A software decoder performs the decoding using the CPU of the host computer such as a PC. Any input device can be used in conjunction with a software decoder (an adapter to plug directly into the serial port of a computer using a software decoder).
Decoding is also performed in the scanner itself, usually in the handle of a decoded scanner. These devices are generally more expensive than the undecoded scanners and usually plug directly into the serial port of a PC, however, some decoded scanners can directly connect with certain terminals.
Some decoders support multiple device input such as magnetic stripe or RS232. The physical connection varies with each manufacturer. The scanning input is generally DB9, RJ11, or RJ45. The serial connection is usually a DB25. A few decoders support a daisy chain configuration in which decoders can be chained together. These decoders are ideal for time and attendance, shop floor control, job-tracking, as well as many other general data collection applications.
Would you like to own a hard copy of this book? If so, please click here to request your free copy. Be sure to include your name, mailing address, and phone number to ensure prompt delivery.
Click here to return to the Table of Contents.
Glenn W. Lee