Bar code scanners are designed to read imprinted bar / matrix code symbologies.  Bar code scanners can be slot card scanners, fixed mount scanners, or hand-held scanners.  Slot card bar / matrix code scanners are designed to read imprinted bar or matrix code cards that are passed through the aperture on the reader.  A horizontal scanner is basically a tabletop, where the code is passed over the scanner face.  A vertical scanner sits on top of a counter or stand where the code is passed in front of the scanner face.  A wand scanner is typically made from 1/2" stainless steel tubing or from plastic; the optics are in the front with a cord out the back. The wand scanner must be moved by the user's hand across and in contact with the bar code. While the wand is moving across the bar code, the reflected light is converted to electrical signals through a photocell in the wand.  A hand held or gun type scanner can be non-contact or near-contact scanner, which generally uses a beam of focused light to read the bar code. The most common form of active non-contact scanner uses a laser beam that is automatically scanned back and forth across the symbol at a high rate. Near-contact scanners utilize a CCD device. Active non-contact or near-contact scanners may be stationary as an option.  Gun type readers can also be fitted with optional fixed mounting.

Bar code scanners can be configured to recognize a variety of bar code symbologies.  These include, but are not limited to, Codablock, Codabar, Code 1, Code 11, Code 128, Code 16K, Code 39, Code 49, Code 93, Data Matrix or Data Code, EAN, Interleaved 2 of 5, Matrix 2 of 5, Maxicode, MSI/Plessey, NW-7 Code, PLANET, POSTNET, Telepen, UPC, and VeriCode.

Bar code scanners can be equipped with one of nine basic user interfaces including integrated graphic display, wand or laser emulation, keyboard connection, serial, parallel, modem, Ethernet, wireless, or PCMCIA (PC Card).  An integrated graphic display is a LCD, etc. to indicate read or decoded info.  Wand or laser emulation needs an external decoder.  A keyboard connection is usually made through a keyboard decoder wedge.  Serial output is a standard digital output protocol (serial) such as RS232, RS422, RS485, etc.  Parallel output is a standard digital output protocol (parallel) such as IEEE488, Centronics port, printer port, etc.  A modem is a modulator-demodulator. A modem is a device or program that enables a computer to transmit data over telephone lines. Computer information is stored digitally, whereas information transmitted over telephone lines is transmitted in the form of analog waves. A modem converts between these two forms.  Ethernet is a local-area network (LAN) protocol developed by Xerox Corporation in cooperation with DEC and Intel in 1976. Ethernet uses a bus or star topology and supports data transfer rates of 10 Mbps. The Ethernet specification served as the basis for the IEEE 802.3 standard, which specifies the physical and lower software layers. Ethernet uses the CSMA/CD access method to handle simultaneous demands. It is one of the most widely implemented LAN standards.  A wireless interface is usually RF or IR.  PCMCIA devices (PC Cards) are credit-card-sized peripherals predominantly used in laptop computers. The PCMCIA adapter takes the place of a COM port on a standard bus. The card is plugged into a 68-pin host socket that is connected either to the motherboard or an expansion bus. An adapter then translates the PCMCIA signals into signals usable by the computer's bus.

Common features on bar code scanners include audible or visual “good reading” indicators, omni-directional reading ability, numeric or alphanumeric keypad included, and memory for data and program storage.