Proximities
Radio Frequency Identification
Radio Frequency Identification (RFID) is like it says: a form of identification by means of radio communication. Over the past decade, RFID has grown out of access control markets and supply chain management and into a much more complete family of products used in everything from item-level tagging (bar code replacements) to measuring lap-times of race cars. More recently, RFID has come to the front page of the business section in articles featuring Wal-Mart's initiative to replace bar codes, Mastercard's inclusion of RFID into credit cards, automated toll roads, and dozens of other high tech endeavors. Proximities is paving the way in many areas of RFID technology, such as cost reduction, security, and RFID system integration.
Now, that's all great, but what are the benefits of RFID? RFID is fast becoming the preferred means for all kinds of identification because each RFID "tag" can store thousands of bytes of information, which is much more than any type of barcode. RFID has a number of other advantages:
- An RFID tag does not have to be visible to be scanned.
- Hundreds of tags can be read from a single scan by a single reader. This makes RFID great for any sort of automation.
- A tag's performance does not decrease when written on or defaced. Try that with a barcode.
- Users may read or write their own data to RFID tags. For example, most ISO-15693 tags (the type Proximities uses) contain one to three kilobytes of memory. This might not sound like a lot, but in fact it's enough room to store hundreds of codes and ID numbers.
So, what makes RFID different than a normal radio? RFID operation is defined by structured dialog between the tag and the reader. First, the reader sends out a radio message. If a tag is nearby, it will respond to the reader's message with its own message. This is the guiding principle by which all RFID systems operate. The other thing that makes RFID unique is a little bit more complicated. Whereas any system of two radios could just as easily operate in the same reader & tag fashion, RFID tags don't actually transmit a radio signal. Instead, they perform a technique called radar backscatter, which is detectable at short ranges by the RFID reader. By tweaking the variables involved in making a radar backscatter device, the maximum read range of an RFID tag can be adjusted from anywhere between a few centimeters and a few meters. In order to understand the rationale here, consider that for a secure transaction (such as contactless payment), you wouldn't want to be broadcasting radio transmissions for the whole world to hear.
RFID tags come in two varieties: active and passive. Active tags contain their own batteries, and passive tags rely only on power transmitted to them by the reader. Active tags generally have longer read ranges and are more sensitive, which is why they are often used for automated toll roads and train car tracking. Passive tags are smaller, cheaper, and have shorter read ranges, which is why they are preferred as item-level tags, shipping pallet tags, credit cards, and Proximities’ wristbands.