Barcodes and RFID information
 
Q: What is a barcode?
 
A barcode is a method of printing information for a computer to read quickly and easily via a barcode scanner.
 
Barcodes come in a variety of styles, the most common being a series of black and white vertical bars of varying thicknesses to represent the information.
 
A common 1d barcode as used for example on goods in shops will hold around 13 characters of data.

 
Q: When did barcoding start?
 
Barcodes have been with us since the late 1940s when Norman Joseph Woodland and Bernard Silver applied for a patent for their invention. The first retail application was in 1974 and for the trivia collectors among you the first item scanned at a shop in Columbus Ohio USA was a pack of chewing gum. Before that, in the 60s barcoding was used for identifying railway goods wagons although the project was abandoned some years later. In 1981 the US Department of Defense adopted the use of Code 39 barcodes for marking all products sold to the US Military.
 
Q: Are all barcodes the same?
 
In the same way that there are a multitude of spoken languages and typefaces for conveying them there are a variety of barcode fonts or symbologies.
 
1d barcodes are the most widely seen and look like a row of black columns although there are many types of 1d codes.
 
Retail products use EAN13 barcodes and books are marked with a variation on this called ISBN13 (formerly ISBN10 although an extra 3 characters were required to cope with the number of titles).
 
Code 3 of 9 (code 39) and Code 128 are also widely used with the compression capability of code 128, as shown below, being a particularly efficient way to store short numeric data.

 
A type that you will see frequently but may not immediately recognise as a barcode is the peculiar looking RM4SCC version that Royal Mail uses for mail sorting postcodes. Instead of reading the width and spacing of bars the scanner looks at ascenders and decenders, the size above and below a central line. This example contains the postcode OX4 5ZZ 9Z D where 9Z D represents route information.
 
In recent years 2d barcodes have been developed and will hold larger amounts of data. Maxicode is a symbology invented and used by UPS on parcels which uses a pattern of hexagonal dots around a central target. Datamatrix features a pattern of squares with solid edges for alignment and QR Code is a pattern of squares with 3 alignment corner targets.
 
The Datamatrix example below contains the text Pen Mobile Solutions 08700 662217

 
Of course with such a range of barcode types there is a corresponding range of scanners as not all scanners will read all types. Different barcodes are also suited to different applications so we advise you to discuss how you want to implement barcoding with one of our experts.
 
 
Q: What can a barcode tell me?
 
Lets start with a can of beans on the shelf at a supermarket. On the side of this tin is a barcode (a 1d barcode - probably EAN13 symbology) in its own white space with a number printed beneath.
 
A barcode scanner is just a quick way to read the number. Scanning is all about speed and the barcode is simply the numeric item code arranged as black and white bars.
 
If you had a USB barcode scanner plugged into your PC and opened a word processor document or spreadsheet, scanning the barcode would insert the number wherever the cursor is just as though you have typed it.
 
The clever part is a computer application that handles barcode scan. A database is preloaded with the information about the barcodes you expect. At the supermarket this might include, pricing, stock levels, item name, manufacturer etc. The till looks up a barcode, finds the corresponding price and displays it at the checkout. It also alters the stock count.
 
Pen Events webscan aplication does this with visitor barcodes. Each barcode is linked to a visitor record which includes for example whether a visitor has arrived or not. Each scan updates the database record or displays information.
 
Think of the barcode as an address within an application for some information and remember that the application and information needs to be put there by somebody first - without this a scanner is just a fast way to type.
 
 
Q: What can't a barcode tell me?
 
We covered, in the question above, how a barcode is usually used to contain a reference number and an application is used to retrieve information from a database so the usual answer to this is that a barcode doesn't usually tell you information. (An exception to this might be if you encoded a lot of data into a 2d barcode although in some cases this can raise privacy or security issues so it isn't advisable).
 
A barcode can also not confirm whether it is genuine or a copy. The sample generator on this page shows just how easy it can be to make a barcode and a scanner will just read the data contained and process it whether it is on the correct ticket, can of beans or a sheet of paper. For this reason it is always necessary to include a level of visual checking of the ticket/pass/badge/coupon in your processes. Note there are some safeguards that are built into some Pen Events barcode reading solutions although if you want to avoid this problem it may be worth considering RFID tags which contain additional security information and cannot be cloned in the same way as a barcode.
 
 
Q: What is RFID?
 
Radio Frequency IDentification, or RFID, is a generic term for technologies that use radio waves to automatically identify small tags.
 
 
Q: What is an RIFD tag?
 
RFID tags are comprised of a microchip that is attached to an antenna. The chip and the antenna together are called an RFID transponder or tag. Tags can be thinner than paper and smaller than a fingernail.
 
The antenna enables the chip to transmit the identification information to a reader. The reader converts the radio waves reflected back from the RFID tag into digital information that can then be passed on to computers that can make use of it.
 
RFID tags can be incorporated visibly or invisibly into key-fobs, wristbands, tickets, tokens, badges and more.
 
 
Q: Is RFID better than barcode scanning?
 
RFID and barcoding are different ways to achieve similar aims. Each has advantages. As barcodes are simply printed they are cheap and easy to produce whereas RFID tags are a more expensive manufactured item. RFID tags, on the other hand, can contain more information and only need to be within range of a reader to be identified. Furthermore the data encoded on the tag can be altered and re-written during the read process making the contents variable to suit your needs.
 
 
Q: Where is RFID used?
 
The best example is the Oyster card which contains an RFID tag to identify the user. 10 million of these are in circulation used for 38 million London Underground and bus journeys every week. (source:www.tfl.gov.uk)
 
 
Q: What is the range of an RFID tag?
 
The tag range depends upon tag type & design and the RFID reader. The MiFare tag used in Oyster cards has a maximum theoretical range of 10cm although in practice around half this is usual. A major contributing factor is the size of the antenna (a small wire or foil coil); a large antenna such as that found in a credit card size/shape tag will give better results than a small antenna in a plastic coin tag for example. An active tag of a different design can have a range of many metres although cost is prohibitive for applications like visitor tracking and access control.
 
 
Q: What frequency do tags use?
 
There are 3 frequency bands for RFID technology: LF 125kHz, HF 13MHz, UHF 900MHz. Each has different intended uses, tag size, range and manufacturing costs. In addition to this there are both active and passive versions where active tags have a power source to increase range (and cost rises to reflect this).
 
 

 
 
 
Make a sample 1d code 39 barcode
max 3 characters
Make a sample 2d datamatrix barcode
max 64 characters

Please note that the barcodes shown here in blue are intended for demonstration only and due to reduced contrast compared with black on white are unlikely to scan effectively. Also note that barcode length has been restricted in these examples.
 

 
 
 
 

 

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