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Frequently Asked Questions
Q: What is Radio Frequency IDentification (RFID)? A: RFID is the term used to describe technologies that use radio waves to identify people, animals, or objects. The most common method of identification involves storing a serial number that uniquely identifies an object, such as a library book, on a microchip that is attached to an antenna. The term, RFID tag, refers to this combination of chip and antenna. The antenna enables the chip to transmit the identification information to a reader that converts the radio waves from the tag into computer-readable, digital information. RFID tags used in libraries usually have a security bit that is automatically turned off and on as an item is checked out and in. Some tags may also offer the option of including other information, such as item type, ownership, or multi-part set information.
Q: How does an RFID system work? A: The reader sends out electromagnetic waves that the tag antenna is enabled to receive. When the tag antenna enters the RF (radio frequency) field, the tag's microchip circuits are powered by signals created by the reader. These signals are transmitted within the RF field. The chip modulates the waves and the tag sends them back to the reader. The reader converts the signals received from the tag into digital data that gets sent to a computer.
Q: Do RFID and radio waves pose any health risks? A: Electromagnetic waves are transverse waves produced by the motion of electrically charged particles. They have both electric and magnetic components. Electromagnetic waves are classified according to their wavelengths on the electromagnetic spectrum—the shorter the wavelength, the higher its frequency. The electromagnetic spectrum is divided into eight major regions: cosmic rays, gamma rays, x-rays, ultraviolet rays, visible light, infrared rays, radio waves, and power frequencies (electricity). RFID systems use low frequency radio waves that are equivalent to the electromagnetic waves used in radios, TVs, video games, or microwave ovens. These waves are non-ionizing and are not powerful enough to cause serious damage to our health.
Q: What makes using RFID different from using bar codes? A: RFID and bar code technologies are different although their applications sometimes overlap. The primary difference is that bar code readers require a direct line-of-sight to scan the bar code label; RFID readers do not. When scanning bar codes, a scanner has to “see” the bar code to read it. In order for the scanner to read a bar code label, a patron or librarian must position the label so that the scanner is properly aligned with it. In addition, if bar code labels fall off, tear, or get soiled, scanners cannot read them. RFID tags, on the other hand, can be read as long as they are within range of a reader, even if covered with protective labels. The tags can be safely applied inside of materials as opposed to the outside of covers and cases. Multiple items can be read simultaneously. And while bar codes contain the item ID only, RFID tags can be programmed to hold whatever information the system designers (or library) choose to store.
Q: On what frequency does a library RFID system operate? A: RFID tags and readers have to be tuned to the same frequency to communicate. RFID systems use radio waves at many different frequencies, but generally the most common are low (around 125 KHz), high (13.56 MHz), and ultra-high frequency (UHF, 850-900 MHz). Library RFID system operate at high (13.56 MHz) frequency which is appropriate for the targeted reading of item-specific tags within relatively short ranges. However, other systems (like those used in warehouse environments), use ultra-high frequency. As a result, the tags and readers that might be used at Walmart are not compatible with those used in a library.
Q: How are passive and active tags different? A: Active RFID tags have a battery that powers the microchip's circuitry and enables the tag to send a signal to a reader. A familiar use of active tags is in toll-booth applications that allow drivers to pay without stopping. Active tags have a far read range (100 feet or more). Passive tags, which are used in libraries, have ranges that rarely exceed two feet, and for many applications, no more than six inches. Passive tags don't have batteries, making them smaller and less expensive. They draw power from the reader. The reader sends out electromagnetic waves that power the tag's circuitry when the tag enters the electromagnetic field.
Q: What’s the difference between read-only and read-write tags? A: Microchips in RFID tags can be Read/Write (R/W) or Write Once/Read Many (WORM). With R/W tags, you can write over existing information (unless it is locked) when the tag is within reader's range. The ability to turn security bits off and on requires an R/W operation. WORM tags don’t contain a security bit that can be changed; in order to determine if an item is properly checked out, the security gates must read a tag’s entire bar code number, use software to communicate that number to the library’s database, and wait for a response that tells the item’s checkout status.
Q: Can there be a problem reading multiple tags at the same time? A: When multiple tags are sending signals to the reader at the same time, the reader can get confused. Each vendor has a different solution for reading all the tag signals sent. The time to read a tag is measured in milliseconds. Even though it appears that tags are read simultaneously, in fact, they are actually read sequentially, just at a very rapid pace. Anti-collision technologies employed by many RFID vendors help in multiple tag environments. When applying RFID tags to a library collection, tag placement should be staggered to prevent tags from being perfectly aligned with each other. This assists the readers in the recognition of every tag.
Q: Can RFID tags be read even when there is something between the tags and the reader? A: RFID tags can be read through wood, plastic, and even liquid. However, they cannot be read through metal. This means that RFID readers can be placed beneath wood desks. On the other hand, tags that are placed inside of books with metallic covers will not be read. Additionally, because of the metallic content of CDs and DVDs, tags placed directly on disks may not always be read successfully. CDs and DVDs become even more problematic when individual disks are tagged as pieces of a multi-part set.
Q: What is the read range for a typical library RFID tag? A: Read range may vary with the application. Most security pedestals can read tags at a distance of 18 inches while most other applications read at a range of approximately 6 inches. This is done intentionally so that only the tags really close to the reader are read and other nearby tags are ignored.
Q: Are there any standards for RFID used in libraries? A: There is no standard specific to RFID used in libraries. The International Standards Organization (ISO) officially established the first standard for RFID communication protocols (ISO 18000-3) in September 2004. The goal of this standard is to define a standard set of communication guidelines for 13.56 MHz RFID tags. An earlier standard, ISO 15693, developed for non-contact access cards, has been incorporated into ISO 18000-3 and is commonly referred to as the relevant standard for libraries. Both of these standards, however, are technology standards, not application standards. Efforts are now being made in various standards committees, such as NISO, to develop a common RFID application protocol that would specify both what information should be stored in a tag, where it should reside, and how it is encoded. The goal of this standard is to allow complete interoperability of tags and readers from various vendors.
Q: Will RFID hardware interfere with other electronic devices in the library? A: RFID hardware will not create any interference with current security systems, PCs, phones, or other electronic devices.
Q: Is the system in any way harmful to library materials, including audio-visual materials? A: No.
Q: Are there any issues of patron privacy affected by the implementation of an RFID system? A: Bibliographic information (author, title, call number) should not be programmed into the tag. The Integrated Technology Group endorses the resolution the ALA Council adopted at the midwinter meeting of the American Library Association on January 19, 2005 concerning RFID and privacy principles.
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