Fixed Mount Bar Code Scanners

Fixed mount bar code scanners are typically used as point of sale devices. They are designed to manually or mechanically read bar codes or matrix codes passed by their scan windows. Unlike hand scanners, they are affixed to a single location.

Fixed mount bar code scanners are available in two distinct configurations, either horizontal or vertical.  Horizontal devices are also referred to as in-counter scanners.  These scanners are hardwired into a counter or tabletop, often with a piece of glass over the device to protect it, while allowing the scanning beam to penetrate.  Products being scanned are simply swiped over the face of the glass and are read by the scanning beam.  These devices are most commonly seen in supermarkets.  Vertical fixed mount bar code scanners are similar to horizontal devices except that they are placed onto a counter, or hardwired into a wall or shoot-side.  There are no performance differences between the two configurations.  The choice of style simply comes down to space available or preference.

Fixed mount bar code scanners use two different optical head technologies to read and encode data.  Some fixed mount bar code scanners use a laser diode to create a scan line by projecting a beam of energy off a rotating mirror or prism. This noncontact device allows for a large depth of field.  The second optical head type uses CCD or LED technology. CCD stands for Charge Coupled Device, which uses one or more LEDs to flood the bar code area with light, and an image of the code is transferred to an array of photodetectors. It is a near contact or contact device, with a smaller depth of field than a laser.

Both scanning methods (LED vs. Laser) result in a digital signal that must be translated into recognizable, or computer-compatible, data.  Using an algorithm, the decoder identifies and interprets each bar coded or matrix coded message, and transmits that data to the host computer or utilizes it for additional purposes.  The most common decoder types used by fixed mount bar code scanners are keyboard wedge decoders and software wedge decoders.  The term "wedge" refers to any device inserted between the scanner and the terminal that translates the digital signals into usable codes.  Keyboard wedge decoders send data in key codes, as though the data had been keyed through a keyboard.  The decoder software resides in a keyboard wedge placed between the scanner and the terminal or host.  Software wedge decoders connect directly to the control PC and its installed software decodes the barcode or matrix code data.

Less common decoding methods used in conjunction with fixed bar code scanners include integral decoders, in which the scanner is a stand-alone device, with integral decoding software; and uncoded devices, which send raw digital signals that need decoding by an external decoder before use.

Pages: 1 - 3 of 208