Hand Held Contact Scanners
Hand Held contact scanners are very low cost, low power consumption devices suitable for relatively low volume applications.

These devices use LEDs to provide the light output, and usually must come in physical contact with the barcode to perform a read. Many of these scanners have a trigger that must be pressed to perform a read, though others can sense when they come close to an object, and turn on the LED's automatically.

There are a few very low cost models from unknown manufacturers, that have very poor read capability. If considering this type of scanner, it is a good idea to test the device to ensure that it does read properly. Most are very good, but there are a few that make life difficult due to bad read rates.

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Hand Held Laser Scanners
Handheld laser scanners do not need to come into physical contact with the barcode, and can read labels at distances ranging from a few inches to several feet.

When the trigger is pressed, a red line of laser light is emitted, and this needs to be pointed so that it crosses the width of the barcode.

These scanners are low in cost, and are particularly useful when you need to read barcodes on heavy items in a shopping cart, and presentation of the device to the scanner might be difficult.

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Presentation Scanners
Presentation scanners offer a big advantage because they offer hands free operation. These scanners can range from low cost units to very expensive models. These scanners require that the barcode be presented to the scanner, or passed in front.

Vertically mounted scanners such as this one, are usually better than horizontally mounted scanners where dirt can collect on the glass, requiring more frequent cleaning, and the risk of scratching the glass is greater.

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Built in Scanners
Combination devices such as this Magellan 8200 Scanner and Scale offer the highest quality and performance however they need to be built into the checkout lane by shopfitters, and the flat metal top would be level with the top of the counter.

This particular device has a rotating prism inside, which reflects the laser light in many directions so that virtually any barcode can be scanned from any angle. The laser light is emitted from both the base of the unit as well as the side making it even easier to get a good read.

In addition, this device is an electronic scale. Items to be weighed are placed on top of the unit, and prepackaged item passed over it.

In high volume applications such as supermarkets these device are excellent. But of course, the shopfitter will probably charge more to install this type of device than the entire cost of a CCD handheld scanner...

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Serial
Serial RS-232 interfaces are the most common way of connecting barcode scanners, and are almost always used for built in or presentation scanners. More information is available about Serial Cabling and Interfacing if this information is not readily available from the manufacturer.

Serial interfaces always require a separate power supply for the scanner. Larger presentation scanners will require a separate power supply in any case, but smaller hand held scanners may be able to operate using power from a USB or keyboard wedge connection to the computer.

Serial connections can be plugged and unplugged from the system while it is running without damaging the hardware.

Serial interfaces always send their data to the application controlling the serial port. Refer to the discussion below with keyboard wedge and USB to understand why this is important.

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Keyboard wedge scanners have a plug and a socket on the cable, and are inserted into the cable between the keyboard and the computer. With a keyboard wedge, the scanner draws power from the keyboard cable, so no separate power supply is required.

Many POS systems operate using a touch screen, without a keyboard being connected. Some keyboard wedge scanners will not operate unless a keyboard is connected. If you are considering using a POS system without a keyboard connected, and you want to use a keyboard wedge scanner, you should check that this will work with the devices you are considering.

Keyboards, and keyboard wedge scanners can not be plugged and unplugged from the host system while power is applied without causing hardware damage. Many people do this, but they are playing Russian Roulette. To connect or disconnect a keyboard wedge scanner you must shut down the computer.

Keyboards (and keyboard wedge scanners) send their data to the application on the computer which has the keyboard "focus". If you are only ever running a POS application on the computer this will probably not matter. But if you have a music program running in the background, or you are playing a game because no customers are in the store, and the other program is active (i.e. the title bar is highlighted) then when you scan an item the data will be sent to that application, not the POS software.

Some very cheap, very nasty CCD handheld scanners we have seen, that use a keyboard wedge interface, have not implemented their firmware correctly. In particular, when scanning Code 39 Alpha barcodes, they return upper or lower case depending on the state of the Caps Lock key on the keyboard. Code 39 does not contain lower case letters in its character set, and this can cause problems in many cases.

You can test this by printing some customer cards in SELLmatix Control, and then scanning them into Notepad. If the data read changes case according to Caps Lock, you have one of these devices, and we would suggest you choose a different scanner model.

If you have already "stuck" with this kind of device, SELLmatix POS allows you to "Force" all characters to upper case in the barcode reader configuration dialog.

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USB is relatively new, and USB Scanners normally have drivers where they appear as a "Human Interface Device" which emulates a keyboard, but does not go through the generic Windows keyboard driver.

Many smaller USB barcode scanners can be powered by the USB interface, which eliminates the need for a separate power supply.

USB devices can be plugged and unplugged from the system while the power is turned on, but if an option appears to "Safely Remove Hardware" for the device then it should be used.

Problems with USB scanners are rare. We have seen a couple of cases where the computer did not detect a USB barcode scanner if it was already plugged into the computer when it was turned on. In these cases the problem could be resolved by unplugging the scanner and then plugging it back in. These were not computers or scanners that we supplied, and we don't know if the problem was with the scanner or the computer. If you are considering a USB scanner, then it might be worth checking that this is not a problem with you computer hardware.

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