Barcode Scanners - Types of Connectors

Most barcode readers use a PS/2 or USB cable for output: PS/2 cables are connected to the host computer in a Y formation, the PS/2 keyboard port with its first end, to the keyboard with its second, and to the barcode reader with its third end. The barcode characters are then received by the host computer as if they came from its keyboard decoded and converted to keyboard input within the scanner housing. Many readers can also be equipped with an RS-232 output port so that the decoded characters arrive at the computer via one of its RS-232 connectors. USB is supported by many newer scanners, in many cases a choice of USB interface types (HID, CDC) are provided.

There are a few other less common interfaces. The proprietary IBM interfaces (port 5B, port 9B and port 17) that use an SDL type connector and are based on an RS485 protocol. OCIA is sometimes still found, mostly used on older stand alone cash registers with a wide variety of connector types. Undecoded interface is an amplified output of the raw wave received back from the barcode and requires a decoder to be built into the terminal that the scanner connects to which is more common on industrial terminals. Wand emulation is another output type that takes the raw wave and decodes it, normalizing the output so it can be easily decoded by the host device. Wand emulation can also convert symbologies that may not be recognized by the host device into another symbology (typically Code 39) that can be easily dec