Disadvantages of the keyboard wedge 1. Disadvantages of the keyboard wedge Simple and easy to interface to the computer. Advantages of the keyboard wedge Simple and easy to interface to the computer. A bar code reader with keyboard wedge output plugs directly into the keyboard port on your computer and also provides a pigtail connector to plug in your keyboard simultaneously. Bar code readers come in either “keyboard wedge” output or RS232 output. The reader then uses sophisticated digital image processing techniques to decode the bar code. The main difference between a CCD mobile barcode scanner, a pen type barcode scanner, and laser barcode scanner is that the CCD barcode scanner measures emitted ambient light from the bar code whereas pen or laser scanners are measuring reflected light of a specific frequency originating from the scanner itself. The important difference between a CCD barcode scanner, a pen type barcode scanner, and laser barcode scanner is that the CCD reader is extremely small and because there are hundreds of sensors lined up in a row in the head of the barcode reader.
