When you want a barcode scanner (or barcode reader as they are also called) you can get very confused with terminology. I hope that by reading this it may be a little clearer for you. We will start by giving you basic knowledge of how barcodes work and then go into the different types and interfaces of barcode readers. We also have a quick troubleshooting tutorial.

Remember we are here to help you choose so if you need help or need to purchase a reader then just contact us. [↑]

To answer this question you must know a little about barcodes. So let's go through a few points.

1. Why are barcodes usually Black and White? Barcodes are read by an optical process and it is much easier for barcode readers to be able to accurately read the barcode if the "Bars" are non reflective (ideally black) and the "Spaces" are reflective (ideally white). Other colour combinations can work but their success depends on all sorts of criteria such as the colour, the reflectance, the resolution of the printer, the barcode reader.

2. Why is there a big space at the beginning and the end of the barcode? This area is called a "quiet zone" and the barcode reader needs it to determine where the barcode starts and stops. If this quiet zone is missing at either or both ends then the barcode may be able to be read but its chances are not good. [↑]



3. How are the bars and spaces determined? This changes with all the different barcode types but mostly they look pretty similar.

Why do most busy retail outlets use a big hands free multi directional laser barcode scanner costing around $2000 and some others try to make do with a hand held scanner costing around $135? The short answer is because the multi-directional laser model saves them time and money.

Consider a supermarket or busy convenience store which for arguments sake may scan 2000 items per day (a conservative estimate). By using a hands-free multi-directional laser scanner as opposed to a hand-held ccd scanner, conservatively, a time saving of half a second can be made. This represents a 16.6 minute saving a day per terminal. This is a significant saving and in some cases may negate the need to deploy an extra operator in those busy periods that are part of the retail environment.

This situation illustrates that not all requirements can be satisfied using one type of scanner. This is why Gripon Mobile Solutions have a huge range of scanners which we are able to recommend for different applications.

So how do you choose? You can ask for advice but before you do, consider these questions and work out the answers as they may help you. If you talk to us we will probably ask you these questions too.

1. How much scanning will I be doing? If you are a busy supermarket this is easy to answer but if you are scanning only occasionally then this is an important question.

2. How good are the barcodes I am scanning? Take the time to look closely at the barcodes. If they aren't printed very well then you may need a higher performance (more expensive) scanner or you may need to send us some sample barcodes for testing with various scanners.

3. Are the barcodes close together on the package or the page? You may not be able to use a multiline laser scanner if they are, and you may also need a scanner with CodeGate (explained later).

4. Will I be close to a computer? Do you need to scan away from a computer eg at a dispatch area or scanning bulky items away from the counter. You may need a wireless scanner.

5. What ports do I have available on my computer? This may be a factor in determining the interface type.

6. Do I need to scan 2D barcodes? If you do then you will need to choose the correct reader. [↑]

There are five basic types of barcode scanning devices. The words "reader" and "scanner" are often used interchangeably to describe the device which is used to read a barcode. [↑]

The first type of scanner is the contact wand. These scanners resemble a "wand" or "pen". Barcode Wands were very popular in the 1990s because of their low cost when compared to other types of scanners at the time. These days the cost of the wand is similar to better solutions on the market. Wands still have a place in some areas but certainly in most retail like environments the other barcode readers do a better job.

How Do They Work?
Light from a light source is focused at the tip of the wand. A wand reader has both a light source and a light detector in the same pen-like container. When the tip is placed in contact with a bar code symbol and the wand moved across the bars at a constant rate to scan the symbol, the projected light is reflected back by the light coloured spaces and absorbed by the dark bars. The reflected light enters the tip of the wand. The image of the bar code is seen on the photocell. The photocell signal is sent to decoding circuitry either in the body of the wand or to an external decoder. These scanners must be kept in contact with the symbol throughout the scan. If the symbol is on a curved surface or in a difficult to reach space, contact wands will be difficult to use to successfully read the symbol.

The distance between the tip of the wand and the bar code is critical. The reflected light will only strike the photocell accurately from a precise distance. This distance is the nominal focal length of the wand. Early wands used nylon or plastic tips, and these tips often were worn down from hard use. The shortened length of the tip made the wand "out of focus." Later wands use glass tip crystals and steel tips to resist wear. Some wand scanners have tips which may be unscrewed to replace the tip crystal. If the tip is not tightened, the wand may also become out of focus. Finally, if the bar code symbol is covered by a thick clear laminate to protect the symbol, the spacing caused by the thickness of the laminate may be too great a distance for the focal length of the wand.

In order to decode the information in the bar code symbol, the widths of the bars and spaces must be recognized and measured. To do this the speed of scanning needs to be constant. However, since the wand is scanned over the symbol by hand, the speed of scanning will vary from moment to moment and from person to person using the wand. Since the movement of the wand is variable the decoder/wedge makes some corrections. If the amount of correction exceeds the tolerances in the decoder/wedge then a "no read" will result. These speed tolerances vary from manufacturer to manufacturer. Most barcode wands also need a decoder module which is external to the wand in order to convert the wand data and connect to the computer. [↑]

CCD barcode readers are a popular choice with a lot of people these days. They are inexpensive and are very tolerant to the user. They are shaped often like an "overgrown razor" but the longer range CCD scanners can also be "gun shaped". Traditional CCD scanners have a range of approx 50mm whilst the longer range scanners can read up to about 300mm. Often they are characterized with a fuzzy band of light projected onto the barcode.

How Do They Work?
With CCD barcode readers the bar code label is illuminated by an LED light source. The image of the bar code is focused on to a device called a charge coupled device (CCD). This is where the term CCD barcode reader came from. The Grip2200 is an example of a CCD barcode reader - BUY.

Long-range CCD scanners use very bright LED arrays to increase the depth of focus. This increased depth of field makes it possible to attach these scanners above the counter top for use as a hands free unit. The Grip2400 is an example of this type of scanner - BUY.

The field of view of CCD scanners is limited. This means that they cannot read very long bar codes. Most times the size of the barcode that can be read is only slightly wider than the barcode reader (80mm for the Grip2200). These scanners are available in fixed and handheld forms (ie, on a Stand). With their limited field of view, they operate best with bar code formats of fixed length e.g. product codes etc. These CCD scanners offer a benefit over contact wands since they are able to scan the entire barcode without moving the reader. The major advantages over laser scanners are that they are less expensive and have no moving parts. The failure rate of a Grip2200 - BUY is extremely low. [↑]

In the late 1990s a new type of scanner appeared on the market. This scanner bridged the gap between CCD scanners and Laser scanners. This type of scanner was called a linear imager. Essentially they work the same way as a CCD but using a different pickup sensor. This change meant they were faster and had longer range than the CCDs of the day and had "laser like" performance. The price point was midway between the CCD and the laser. They are often confused with CCDs because they are also characterized with a fuzzy band of light projected onto the barcode. They work in a similar way to a CCD but the pickup sensor and optics are different. [↑]

The next type is the Laser scanner which is probably the most popular type of scanner. You can usually pick one by the sharp/narrow red line which is projected onto the barcode.

Laser scanners are generally faster than CCD scanners and wands and scan from a distance of at least 100mm. The usual range of the laser scanners is between 100mm and 300mm. There are some special use Laser scanners which have a range measured in Metres but these are only used on infrequent occasions. The speed and ease of use of the laser scanner has made the laser scanner the biggest selling type of reader. Due to this sales success the prices of the laser scanners have dropped over time so that the entry level laser scanners are now cheaper than the linear imagers.

How Do They Work?
The laser scanner uses a beam of focused light (Laser Beam) to read the bar code. The laser beam is automatically scanned back and forth across the symbol at a high rate by moving mirrors etc. The light is reflected back to a sensor which then decodes what it sees. The simplest version of these scanners is a single line laser. With the single line laser the barcode must still be orientated so that the laser passes over every bar in the barcode being scanned. For the multi-line laser scanners (like you see in grocery stores etc) the optics are far more complex. Usually a central mirror rotates very rapidly bouncing the laser beam off a series of mirrors located precisely within the scanner. This produces a matrix of scan lines (usually 16-20) all orientated in different places. The barcode can be scanned by any one of these lines allowing the operator to simply pass the barcode in front of the scanner without having to pay attention to the orientation of a laser beam.

The advantage that laser light has over other forms of light is that it can be focused and collimated to a very small beam. This property allows laser scanners to read bar codes on curved surfaces (up to a point). In hand held laser scanners, the collimated beam of laser light is moved back and forth between 40 and 800 times a second. Handheld units generally operate at the lower end of these scanning speeds because the symbol being scanned is usually stationary.

Because of the rapid scanning speed, the narrow beam of a laser scanner appears as a continuous line or geometric figure. In applications where the orientation of the symbol is not known or is not necessary, this line pattern can be a pattern of seemingly many lines (such as with our MS7120 - BUY, left). These patterns ensure that at least one scan will pass over all the bars and spaces in the symbol (provided the height of the barcode is within set limits). Handheld self scanning laser readers generally produce a thin horizontal line which is aimed at a symbol. Often this visible line is only used for aiming an invisible laser bar code reading beam.

With our Single line laser scanner (MS9540 - BUY, left) the scanner sits on a stand and you can use it as described above or with the scanner resting on the stand. This allows you to use both hands and scan without touching the scanner. Additionally this scanner has a feature called CodeGate. The CodeGate feature is designed for applications where there is a possibility of scanning the wrong barcode symbol. A good example of this is a hardware store where they often scan catalogues etc for items such as nails, screws and bolts. The CodeGate feature allows the scan line to be on (and visible) but will not trigger a scan until the CodeGate button is pressed.

An accurate scan of any bar code requires at least one successful pass. Since self scanning laser readers scan at a high rate, they are able to read a poorly printed bar code (those which may take several scanning attempts) without the user noticing. The "smarts" inside the reader analyse a number of reads to come up with a good read result.

Laser scanners are the industry leaders in both performance and the number of laser scanners that have been sold and are in use. [↑]

Imagers are a relatively new type of barcode reader. The Imager type reader is actually a camera. It basically takes photos of the barcode and then some very smart electronics analyse this image and determines if it is a barcode, what type it is, and what the output should be. Early imagers were quite slow, but as electronics have got faster, so have the imager scanners performance. They are now almost as fast as CCD or laser barcode readers.

The major advantage an imager has over other readers is that they can scan 2D barcodes. These types of barcodes carry much more information than a standard barcode but only imagers can read all the 2D barcode types. An example of a 2D barcode is the postal barcode that you can see on some of your mail (usually above the name/address. Another example can often be seen on freight labels.

Imager scanners are usually only used when you need to scan a 2D barcode as they are much more expensive than a standard barcode reader. An example is the MS1690 - BUY. [↑]

There are many different types of interfaces available, below is a brief description of the five most common types. [↑]

The keyboard wedge interface is the most common way to incorporate barcode technology with data management systems that are already in place. The keyboard wedge interface is used primarily on PCs. Barcoding is the most accepted alternative to keyboard entry. It is certainly faster than manual typing and much less prone to error. The question is, how to incorporate a barcode scanner in the place of, or in addition to, the keyboard that was previously used. The answer is; a keyboard wedge.

What exactly is a keyboard wedge? A keyboard wedge is usually hardware. Let's look at the hardware type first. It's called a wedge because it used to be a separate piece of equipment which "wedges" in between the system keyboard and the computer. The wedge interface these days is built in as part of our scanners and not a separate item. Physically, the keyboard plugs into the wedge and the wedge plugs into the computer. When you type on the keyboard, the characters are sent to the computer as usual. When you scan a barcode, the barcoded characters are converted to keyboard "key codes", and sent to the computer. So, the computer thinks that the barcode data the scanner read was typed on the keyboard.

This means that when you want to test a scanner of this type you need only open any word processor or typing package and scan a barcode. The Barcode number or text will be displayed on the screen if all is well. This method of testing allows you to check the scanner without worrying about interfering with the data in your application software.

There are two sizes/types of keyboard plugs; these are referred to as PCAT or PS2. The PCAT plug is 13mm in diameter whilst the PS2 plug is 9mm. If you need to convert between the two then a simple PCAT to PS2 adaptor set is required. This set of adaptors costs approx $15. All our scanners today come suitable for both types of fittings. [↑]

USB interface scanners are becoming very common these days. From Windows 98SE on, there has been inbuilt support for USB keyboards. USB barcode scanners are made to "look" like a USB keyboard to the computer. When you plug in the barcode reader the computer thinks you have plugged in a USB keyboard device and automatically sets up the software for that. From this point on they work exactly like the keyboard wedge reader described above. [↑]

A serial scanner is generally used in situations where a traditional Keyboard wedge scanner cannot be used. Cash registers often use serial barcode scanners. This is probably the most common use of this type of interface these days. Most cash registers use standard serial connections whilst others can use a serial connection with a protocol called OCIA. This is really just a special type of serial connection.

Another common use for serial scanners is on Terminals. Terminals are workstations which are generally connected to a server or mainframe computer and have no internal computing capability. Usually the keyboard plugs directly into the terminal alongside the (serial) network connection. In order to connect a barcode scanner to these terminals we need to connect a serial scanner in between the terminals serial port and the network connection. When barcodes are scanned the serial scanner sends the data back to the host (server/mainframe) computer as if it were sent from the keyboard of the terminal. The host then responds by sending the information back to the screen to be displayed. We have a variety of scanners which can handle this situation.

Some PC software applications also require serial scanners. This is usually done when the software needs to know the difference between a barcode scan and a keyboard entry. Scanners are plugged into the COM Port of the PC, usually COM1 or COM2.

When setting up a serial scanner it is important to have the serial communication settings match the host systems serial communication settings or they will not communicate properly with the computer or terminal. Serial scanners often need a plug pack to provide power to them unlike PS2 and USB scanners that get their power from their respective ports on the PC. [↑]

The most common use these days for this type of interface is as a replacement scanner (CCD or Laser) for a barcode wand. This interface allows a direct replacement of the wand with a higher performance Scanner. We often use this interface to provide scanners for portable data collectors which use a wand. It makes an upgrade a far cheaper option. [↑]

This type of barcode scanner is simply a barcode scanner without a cable. Usually all the interface types above are available with a cordless barcode scanner. These should not be confused with PDEs (Portable Data Entry units) which you may use for stocktakes etc. Cordless barcode scanners are simply a barcode scanner wirelessly connected to a receiver (usually a charging cradle). The receiver is then physically connected to the computer using one of the above interface types. An example of a cordless barcode scanner is our MS9535 - BUY.

Cordless barcode scanners are used in situations where the cable of a standard barcode scanner is a limitation for the user. A common use is in warehouse dispatch areas. The user can freely go over to a pallet of goods and scan the barcodes they need without bringing all the goods back to the computer. Another common example is a hardware store. Large and bulky items are more easily scanned away from the actual counter. [↑]

If you would like to purchase a barcode reader, barcode fonts, printing software etc just call 1800 242 548 or email sales and we will discuss your needs with you. [↑]

If you need further help, would like to be advised of future tutorials, or have a tutorial suggestion just email us.

This tutorial is copyright Gripon Mobile Solutions Pty Ltd. You are free to distribute this or publish this to others provided it is distributed without changes and complete. Whilst every care has been taken to ensure the accuracy of the information provided, no warranty whether implied or stated is given as to the information's accuracy or suitability. As we are not aware of your exact situation the content is used at your own risk entirely. [↑]

Ces Luscombe has worked in the Barcode and POS industry since 1995. Ces is the founder of The Barcode Approach (later to become Gripon Mobile Solutions) and is also the founder of Grabba International Pty Ltd. Grabba International was formed as a result of a spinoff from Gripon Mobile Solutions Pty Ltd after the successful worldwide launch of the Grabba PDA Data Capture attachments in San Jose, California in 2002. [↑]

Gripon Mobile Solutions is one of the leading suppliers of barcode and POS equipment in Australia. As a leading distributor/supplier for the major brands in the industry Gripon Mobile Solutions can help you with any hardware requirements. Gripon Mobile Solutions also has specialists in the Mobile Data Capture and Communications areas. For information on products or advice on suitability contact us on 1800 242548. [↑]