One of the most common methods of reading barcodes is with a hand-held barcode scanner. The barcode scanners all have built-in decoders and can read several different bar code types. Most of the barcode scanners receive their power from the PC keyboard or USB port so no external power supply is required. When a barcode is scanned in, the data is sent to the PC as if it had been typed on the keyboard.Most barcode scanners can read common linear symbologies, such as code 39, UPC, EAN, Code 128 and Codabar, if it is enabled in the scanner. Keep in mind that most scanner manufacturers usually ship new scanners with most symbologies disabled, so make sure the symbology is enabled before attempting to scan. It is possible to scan barcodes that are printed at very small x dimensions (the x dimension is the width of the narrow bar in the code). Before attempting to read barcodes that are printed with small x dimensions, check the barcode scanner manual to make sure the scanner can read it. Also, make sure the printer can accurately reproduce barcodes at these sizes.As of recent – smart phones with cameras can also scan barcodes using the right application.There are also laser barcode scanners, but they cannot always read the small x dimensions that the CCD models can. However, laser scanners are able to read wider barcodes better.