There are many types of barcode scanners out on the market ranging from inexpensive wonds that look like pens all the way up to retail table scanners that are very fast and accurate. The scanner you select depends on your needs which is dictated by the type of barcodes you will be scanning, the volume and speed at wich you need to scan.
The wand or pen scanner is one of the least expensive scanners in most cases. Although these are easy to use, they are limited in speed and accuracy of what they can scan. These are wonderful for low volume environments where you need to scan simple barcodes. These are used by pressing the pen to the paper and drawing it across the barcode. The light at the end of the pen registers the light and dark bars as the pen passes over them and transmit the data to the receiver. The main drawback to these scanners are the speed at which they can scan with any accuracy. It often takes a little practice to get the timing correct. Too slow or too fast and the barcode won't be recognized. This can limit the number of codes that can be scanned.
A step up from the wand scanner is the hand or table top scanner. These often emit a laser beam that sweeps across the barcode scanning it quickly and accuratly and passing it along to the receiver. Table top units usually emit multiple beams or a single beam which is split or refracted into multiple beams making the scanning process happen faster. The hand held units can emit a laser or use a CCD to pulse the barcode. In either case, the dark and light bars are scanned in much the same way as the wond but faster. The need to learn the timing of the swipe is not needed with these scanners. Instead, the distance and angle of the barcode from the scanner is what is key to a quality scan. Hand held and table top barcode scanners come in both wired and wireless models. The wireless scanners make it possible to move through a warehouse, store or ther are scanning items without being teathered to a computer or POS station. Some wireless hand heald scanner even have keypads on them that allow quantity, descriptions or other information to be entered at the time of the scan process. You have probably seen these types of scanners being used in your local grocery store as inventory is being done. If you have a moderate volume of codes to scan or need portability, these units could be for you.
For situations where high speed, high accuracy scanning is required, a built-in table scanner is required. These are the types of scanners you see at the grocery store. The products are quickly passed over the scanner which often has multiple scanning beams and can read the product form multiple angles. This reduces the need for the person operating the scanner to worry about the exact distance or angle of the barcode to the scanner. This type of scanner is also used in industrial situations where items are scanned as they fly down the production line. These industrial versions are often larger and more robust in their design but they have the same basic functionality built into them.
All of the scanners we have talked about so far are limited to 1D barcodes. These are the codes that are made up of lines and are read as the scanner reads in the dark and light bars. The main difference between the scanners is the speed and accuracy and of course the price. But in general they all serve the same basic function and operate in the same basic way.
There is another type of barcode scanner. These can usually scan the 1D barcodes just like the previous models but they can also scan the 2D barcodes such as the QR Codes which store a great deal of data in a tightly packed area. These work not by sweeping across the barcode in one direction, but by looking at the entire code at one time both vertically and horizontally. This type of scanner can come in many forms. You may even have one of these built into your phone. These full image scanners come in many price ranges. The version you have on your phone may have been free or cost only a couple dollars. Larger versions are available as hand heald, desktop and even industrial scanners. Just like the 1D scanners, what you scan and how often you scan will determine which type of scanner you need. For the average individual the low end scanner is normally enough but businesses will find that more reliable and faster scanners are a better investment even though they are more expensive.
As with any product, it is important to determine your need before you make your purchase. And whend possible it is a good idea to test out the scanners before spending a great deal of money.