Barcode Scanners On eBay

Tethered or cordless? You have the option to get a scanner that has a cable connected to the handle of the scanner and the other end of the cable connects directly to the PC. The connection to the PC can vary. Choices are typically USB, PS/2 keyboard wedge and serial. More about interfaces later.

You can get a cordless unit. Cordless barcode scanners have a base station that connects to the PC with a cable. The barcode scanner communicates to the base station via radio frequency. It works a lot like a cordless telephone. Newer cordless systems have a bluetooth connection from the barcode scanner to the cradle. The cordless barcode scanners available today are typically capable of working at ranges of 33 feet or 330 feet. Most applications require only a 33 foot range. About the only time you'll need more than that would be for a warehousing application. But heed this warning - the farther away you get the farther you have to walk back to the host system to verify the data actually made it to the host application. It doesn't happen a lot, but there are times when you will need to verify the data was entered correctly. If you're 100 feet away that's a long way to have to walk, especially if it's multiple times per day. Cordless systems also use a battery in the scanner. Just about every cordless system on the market today uses a lithium-ion battery and they last a long time. The Honeywell 4820 cordless barcode scanner was tested at 1 scan every 5 seconds and it lasted for just over 16 hours. That was on a full charge. When the scanner is not in use you will leave it in the cradle where it would get charged. Needless to say the battery will last well over a full shift without being charged.

Corded or cordless - the choice is up to you. If freedom to move away from your host computer is not needed, then a corded scanner is going to be a cheaper alternative for you.

If you've never worked with a barcode scanner you might be wondering how the scanner connects to a PC or a host computer. I'll explain the most common connection types here.

• PS/2 - If your computer has a PS/2 style keyboard connecter you can "wedge" the scanner between your keyboard and your PC. In fact this style connection was typically called PS/2 wedge. To make the connection you disconnect your keyboard from your computer. The cable connected to the scanner will have two PS/2 style ends. One female and one male. Simply connect your keyboard to the female end of the scanner cable and connect the male end of the scanner cable to your computer's PS/2 keyboard port. Don't mistakenly plug the scanner into the mouse port. Once you have the scanner connected, each time you scan the barcode with the barcode scanner, the data will be placed at the point of your cursor.
  

  

• USB keyboard emulation - By far the most common type of connection today is USB keyboard emulation. Simply plug the scanner cable into an open USB connector on your computer. If you're running Microsoft Windows or Linux the USB keyboard driver needed for the scanner is part of the operating system. That driver will load automatically when you plug the scanner in if the computer is powered on. Or it will load the next time the computer is powered up. Just like the PS/2 connection, when you scan a barcode the data from the barcode scanner will be placed at the point of your cursor.


• RS232 - Most newer laptop computers and many desktop computers no longer have an RS232 connecter. RS232 is a communication protocol. This post is not a tutorial for RS232. Just suffice it to say that if you use this connection type both the barcode scanner and the host computer must be setup with the same communication parameters. They have to speak the same language. Plus the application you're scanning into will need to support getting data from an RS232 port. Not all applications have this capability. If you're unsure I recommend you speak with your application provider to find out if your application supports RS232. The 9 pin connector shown below is the most popular RS232 connector type.
  

  

• USB serial port emulation - This scanner interface is similar to RS232. The difference being USB serial port emulation uses the USB port and not the RS232 connector type. It's the same USB port that is used for USB keyboard emulation. USB serial port emulation creates a virtual serial port on your computer. If using this interface, just as with RS232, your application must be able to get data from a serial port. Many applications do not support this. Also the driver for USB serial port emulation is not included with the operating system. You must get the driver from the scanner manufacturer. You can usually download it from their website.

Imager based barcode scanners come in two types. Area imagers and linear imagers. You would use an area image based barcode scanner if you plan on reading 2D or 1D barcodes. A linear imager barcode scanner can only read 1D barcodes. So why would you even bother with a linear imager barcode scanner if a 2d imager barcode scanner can read both 2d and 1D barcodes? At this point in time linear imagers are less expensive and offer a greater working range than area imagers. The other type is a laser barcode scanner. Laser barcode scanners are very similar to linear imagers. They use a single line laser and can only read linear barcodes.

To further elaborate on the difference between 2D and 1D barcodes. 2D barcodes look like the Data Matrix shown here.

2D barcodes like this data matrix can hold a lot of data. Depending on the type of data, they can potentially hold up to 3116 characters. Most scanners have trouble reading that amount of data, but it is possible. For a good overview of Data Matrix see this Wikipedia entry. Data Matrix barcode on Wikipedia. There are other 2D barcode types. Aztec, QR Code and Han Xin to name a few.

Linear barcodes are the types of codes you see on pretty much every single product at a grocery store. They can't hold nearly the amount of data that a 2D barcode can hold, nor are they as error tolerant. But they are easy to read and can be read with a very inexpensive barcode scanner.

Finally, working range, also known as depth of field, needs to be considered. Working range is defined as the farthest point at which a barcode can be read minus the nearest point at which a barcode can be read. For example: A barcode can be read out to a maximum distance of 18 inches for a particular barcode scanner. That same barcode can be read at a near distance of 2 inches with the same barcode scanner. The working distance is then 18 inches - 2 inches = 16 inches of working range. An important thing that needs to be taken away from this message is that linear barcode scanners always have a better working range than 2D barcode scanners. At least that's true today. As technology improves 2D barcode scanners are becoming better at getting longer working ranges. It's just a matter of time before the gap is closed down. So when purchasing a barcode scanner think about what you're going to do with it. Most applications do not require the longer working range of a 1D barcode scanner. But there certainly are some that do require a longer working range. Just think about it before you decide which barcode scanner will be the best for you.

I've listed some of the things you should really consider when purchasing a barcode scanner. If you know what you want there is no reason you can't purchase it off eBay. You'll get a really good price. And barcode scanners are very durable. They do not break often so you don't really need to worry about repairs. And typically they are cheap enough that if they do break down you can just throw it away and buy another one.

If you have any questions at all about barcodes, what to look for in a barcode scanner, or if you find a scanner on eBay and you want my advice please don't hesitate to email me. I am always happy to help out. As geeky as it sounds I really enjoy helping people when it comes to barcodes and barcode scanners. You can email me by clicking on contact me button directly below.