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Barcode Scanners

How does a barcode work?

Each character is represented by a pattern of wide and narrow bars. A barcode reader uses a photosensor to convert the barcode into an electrical signal as it moves across a barcode. The scanner then measures the relative widths of the bars and spaces, translates the different patterns back into regular characters, and sends them on to a computer or portable terminal.

There are different barcode symbologies, each with its own particular pattern of bars. The UPC code used on retail products is an all-numeric code; so is the Interleaved 2 of 5 Code. Code 39 includes upper case letters, digits, and a few symbols. Code 128 includes every printable and unprintable ASCII character code.

How do I read barcodes?

First you will need an input device (barcode reader) to read the barcode. Pen Mobile Solutions stocks a vast range of devices to suit various applications and budgets.

A barcode reader, also called a till scanner, barcode scanner or point-of-sale (POS) scanner, is a hand-held or stationary input device used to capture and read information contained in a bar code. A barcode reader consists of a scanner, and a cable used to connect the reader with a computer.

What are CCD Barcode Readers?

A CCD scanner has a better read-range than the pen wand and is often used in retail sales. Typically, a CCD scanner has a “gun” type interface and has to be held no more than one inch from the bar code. Each time the bar code is scanned, several readings are taken to reduce the possibility of errors. A disadvantage of the CCD scanner is that it cannot read a bar code that is wider than its input face.

What are Laser Barcode Readers?

A laser scanner, either hand-held or stationary, does not have to be close to the bar code in order to do its job. It uses a system of mirrors and lenses to allow the scanner to read the bar code regardless of orientation, and can easily read a bar code up to 24 inches away. To reduce the possibility of errors, a laser scanning may perform up to 500 scans per second. Specialised long-range laser scanners are capable of reading a bar code up to 30 feet away. Suitable for both retail and industrial applications, progressing technology has also led to laser scanners being available as either tethered devices or cordless.

What’s a 2-D code?

2-Dimensional symbols are generally square or rectangular patterns that encode data in two dimensions. They fall into two general categories: ‘Stacked barcodes’ are constructed like a layer cake of barcodes stacked on on top of the other; they can be read by special 2-D scanners or by many CCD and laser scanners with the aid of special decoding software. ‘Matrix Codes’ are built on a true 2-D matrix; they are usually more compact than a stacked barcode, and they can be read only by a true 2-D scanner.

The primary advantage of 2-D codes is the ability to encode a lot of information in a small space. The practical limit for a standard barcode depends on a number of factors, but 20 to 25 characters is an approximate maximum; 2-D symbols can encode from 100 to about 2,000 characters. The next time you receive a package from UPS look for a 1-inch square label with a pattern of dots and a small bullseye in the center. This is a MaxiCode label, and it is used by UPS for automatic destination sortation. Two other popular 2-D codes are PDF-417 and DataMatrix.

Digital or Imager Barcode Readers?

An image scanner, also called a camera reader, uses a small video camera to capture an image of the bar code and then uses sophisticated digital image processing techniques to decode the bar code. It can read a bar code from about 3 to 9 inches away and generally costs less than a laser scanner. Reliability is equal to if not surpassed by laser scanners as the scan engine within these devices consists of no moving parts, cutting down on the possibility of components becoming loose or breaking if dropped. Suitable for reading 2-D and PDF-417 barcodes.

What is a Keyboard Wedge (KBW)?

Type of connector on a cable, enables the user to plug the device into a PC and keyboard. The cable plugs into the scanner at one end, usually an RJ45 type plug, from the scanner the cable then splits into two barrel type connectors. In this configuration, the scanner is ‘wedged’ between the PS/2 port on the PC and the keyboard, allowing users to input data without worrying about changing the existing setup.

What is a USB?

Connector that allows the user to plug a device straight into the USB port on a PC or till.

Thermal Transfer and Direct Thermal Printers, Printing & Barcode Labels

How can I print barcode labels?

Barcode labels can be printed from any standard dot-matrix or laser printer, however it is recommended that a thermal printer be used. Thermal printers have been designed specifically for printing barcode labels and are therefore better suited to the task. They can print one label at a time or whole rolls at a time, with various print speeds available to suit your application.

What is DPI?

Dots per inch (DPI) is a measure of printing resolution, in particular the number of individual dots of ink a printer or toner can produce within a linear one-inch (2.54 cm) space. Up to a point, printers with higher DPI produce clearer and more detailed output, therefore applications where smaller, denser codes are needed the higher the DPI.

Will I need software to run the printer?

Most printers come packaged with the necessary printer drivers, which will allow you to print from basic packages such as word. For the best results we suggest using Barcode Label Design Software which is flexible, easy to use and compliments your application more effectively.

What is Thermal Transfer?

A Thermal Transfer printer uses a thin plastic ribbon with a thin coating of wax or resin based pigment. The ribbon and labels feed from separate rolls and are squeezed together by a roller as they pass under the thermal printhead . The heating elements in the printhead melt the coating which transfers to the label to form the image.

Produces a durable, high-quality image, and can be used with many types of label stocks (paper and synthetics). Printers are durable and offer relatively fast printing speeds; some models approach 12 inches per second. Cost of printing a single color (usually black) is reasonable, but multi-color printing can be expensive in terms of printer cost and consumption of ribbons.

Excellent for producing product and packaging labels either on demand or in batches.

What is Direct Thermal Transfer?

Direct Thermal labels are made from chemically sensitized paper or synthetics that turn black when heated. A roller advances the labels and squeezes them against the printhead, which contains a row of miniature solid-state heating elements. The printer’s internal microprocessor turns the elements on and off to form the image. Using this type of transfer cuts out the need for ribbons therefore reducing consumable costs. However using this form of transfer does cause more wear on the printhead and should be taken into account when considering this option.

A disadvantage is that direct thermal labels tend to fade over time (6 months to a year), and this process can be accelerated by heat, humidity, and exposure to sunlight. So Direct Thermal is suitable for applications where the lifecycle of the label is very short, such as courier labels.

RFID - Radio Frequency Identification

What is RFID?

Radio frequency identification, or RFID, is a generic term for technologies that use radio waves to automatically identify people or objects. There are several methods of identification, but the most common is to store a serial number that identifies a person or object, and perhaps other information, on a microchip that is attached to an antenna (the chip and the antenna together are called an RFID transponder or an RFID tag). 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.

Is RFID better than using barcodes? 

RFID is not necessarily “better” than barcodes. The two are different technologies and have different applications, which sometimes overlap. The big difference between the two is bar codes are line-of-sight technology. That is, a scanner has to “see” the bar code to read it, which means people usually have to orient the bar code toward a scanner for it to be read. Radio frequency identification, by contrast, doesn’t require line of sight. RFID tags can be read as long as they are within range of a reader. Bar codes have other shortcomings as well. If a label is ripped or soiled or has fallen off, there is no way to scan the item, and standard bar codes identify only the manufacturer and product, not the unique item. The bar code on one milk carton is the same as every other, making it impossible to identify which one might pass its expiration date first.

What are the differences between low (LF), high (HF), and ultra-high frequencies (UHF)?

Just as your radio tunes in to different frequencies to hear different channels, RFID tags and readers have to be tuned to the same frequency to communicate. RFID systems use many different frequencies, but generally the most common are low-frequency (around 125 KHz), high-frequency (13.56 MHz) and ultra-high-frequency or UHF (860-960 MHz). Microwave (2.45 GHz) is also used in some applications. Radio waves behave differently at different frequencies, so you have to choose the right frequency for the right application

What is the difference between a passive, semi-passive and active RFID?

Active RFID uses an internal power source, such as a battery, within the tag to continuously power the tag and its RF communication circuitry. Active RFID allows extremely low-level RF signals to be received by the tag (since the reader/interrogator does not power the tag), and the tag can generate high-level signals back to the reader/interrogator. Active RFID tags are continuously powered, whether in the reader/interrogator field or not, and are normally used when a longer tag read distance is desired.

Passive RFID relies on RF energy transferred from the reader/interrogator to the tag to power the tag. Passive RFID tags reflect energy from the reader/interrogator or receive and temporarily store a small amount of energy from the reader/interrogator signal in order to generate the tag response. Passive RFID requires strong RF signals from the reader/interrogator, and the RF signal strength returned from the tag is constrained to very low levels by the limited energy. Passive RFID tags are best used when the tag and interrogator will be close to one another.

Semi-passive RFID uses an internal power source to monitor environmental conditions, but requires RF energy transferred from the reader/interrogator similar to passive tags to power a tag response. Semi-passive RFID tags use a process to generate a tag response similar to that of passive tags. Semi-passive tags differ from passive in that semi passive tags possess an internal power source (battery) for the tag’s circuitry which allows the tag to complete other functions such as monitoring of environmental conditions (temperature, shock) and which may extend the tag signal range.

Transponder, smart label, Tag. What’s the difference?

Initially, in the technical field, transponder was the term used to designate an electronic module which is able to Transmit information and respond with information. Recently, different fields in which Radio Frequency Identification is prevalent have developed a new jargon to designate the same thing, such as Smart Label or Tag. “Smart labels” are a particularly innovative form of RFID tag and operate in much the same way. However, a smart label consists of an adhesive label that is embedded with an ultra-thin RFID tag “inlay” (the tag IC plus printed antenna). Smart labels combine the read range and unattended processing capability of RFID with the convenience and flexibility of on-demand label printing. Smart labels also can be pre-printed and pre-coded for use. In on-demand applications, the tag inlay can be encoded with fixed or variable data and tested before the label is printed, while the label can contain all the bar codes, text, and graphics used in established applications. Smart labels are called “smart” because of the flexible capabilities provided by the silicon chip embedded in the tag inlay. A read/write smart label also can be programmed and reprogrammed in use, following initial coding during the label production process.

WHAT IS AN RFID READER?

A reader is basically a radio frequency transmitter and receiver, controlled by a microprocessor or digital signal processor. The reader, using an attached antenna, captures data from tags then passes the data to a computer for processing. As with tags, readers come in a wide range of sizes and offer different features. Readers can be affixed in a stationary position (for example, beside a conveyor belt in a factory or dock doors in a warehouse), portable (integrated into a mobile computer that also might be used for scanning bar codes), or even embedded in electronic equipment such as print-on-demand label printers

Is RFID new? 

RFID is a proven technology that’s been around since at least the 1970s. Up to now, it’s been too expensive and too limited to be practical for many commercial applications. But if tags can be made cheaply enough, they can solve many of the problems associated with bar codes. Radio waves travel through most non-metallic materials, so they can be embedded in packaging or encased in protective plastic for weatherproofing and greater durability. And tags have microchips that can store a unique serial number for every product manufactured around the world.

What is the purpose of RFID?

RFID allows data to be transmitted by a product containing an RFID tag microchip, which is read by an RFID reader. The data transmitted can provide identification or location information about the product, or specify information such as date of purchase or price.

A disadvantage is that direct thermal labels tend to fade over time (6 months to a year), and this process can be accelerated by heat, humidity, and exposure to sunlight. So Direct Thermal is suitable for applications where the lifecycle of the label is very short, such as courier labels.

Will RFID replace barcodes? 

It’s very unlikely. Barcodes are inexpensive and effective for certain tasks, but RFID and bar codes will coexist for many years.

What is the advantage of using RFID technology?

No contact or even line-of-sight is needed to read data from a product that contains an RFID tag. This means no more checkout scanners at grocery stores, no more unpacking shipping boxes, and no more getting keys out of your pocket to start your car. RFID technology can also work in rain, snow and other environments where bar code or optical scan technology would be useless.

Are there any standards for RFID?

Yes. International standards have been adopted for some very specific applications, such as for tracking animals and for smart cards, which require encryption to keep data secure. Many other standards initiatives are under way. The International Organization for Standardization (ISO) is working on standards for tracking goods in the supply chain using high-frequency tags (ISO 18000-3) and ultra-high frequency tags (ISO 18000-6). EPC global, a joint venture set up to commercialize Electronic Product Code technologies, has its own standards process, which was used to create bar code standards. EPC global has submitted the second-generation UHF EPC protocols to ISO, and it has been approved as ISO 18000-6C, an international standards.

What are the transponder characteristics?

RFID tags are tiny microchips with memory and an antenna coil, thinner than paper and some only 0.3 mm across. RFID tags listen for a radio signal sent by a RFID reader. When a RFID tag receives a query, it responds by transmitting its unique ID code and other data back to the reader. Basically there are 3 kinds of tags- Active, Passive and Semi Passive.

What’s the difference between read-only and read/write tags?

Chips in RF tags can be read-write or read-only. With read-write chips, you can add information to the tag or write over existing information when the tag is within range of a reader, or interrogator. Read-write tags are useful in some specialized applications, but since they are more expensive than read-only chips, they are impractical for tracking inexpensive items. Some read-only microchips have information stored on them during the manufacturing process. The information on such chips can never been changed. A more flexible option is to use something called electrically erasable programmable read-only memory, or EEPROM. With EEPROM, the data can be overwritten using a special electronic process.

How much information can an RFID tag store?

Tags are available with storage capabilities from 512 bytes to 4MB. It largely depends on vendor and whether the tag is passive or active. Data stored in a tag will be determined by the application of the system and appropriate standards. For example, a tag could provide identification for an item being manufactured, goods in transit, or even the short-range location and identity of a vehicle, animal, or individual. This fundamental data often is referred to as a “license plate code,” similar to the information that is stored on a bar code label. When linked to a database, additional information may be accessed through the reader such as item stock number, current location, status, selling price, and batch code. Alternatively, an RFID tag may carry specific information or instructions immediately available upon reading, without the need to reference a database to determine the meaning of a code. For example, the desired color of paint on a car that is entering the paint assembly area on the production line, or a manifest to accompany a shipment of goods.

Can I tag metal objects? Can I tag items that have high-water content?

Yes. Radio waves bounce off metal and are absorbed by water at higher frequencies. While that can make tracking metal objects or those with high water content problematic, well-planned system design and engineering can solve these issues.

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