That would depend, to some degree, on the nature of the secure room, as well as what you would like the solution to accomplish. Many companies employ passive high-frequency (HF) RFID technology. 3M developed a file-tracking solution that uses passive HF tags. And the U.S. Tax Court deployed 3M’s system to track and retrieve its approximately 100,000 case files, as well as a library of 30,000 books, periodicals and documents stored within its Washington, D.C., office.
Passive HF tags can be read from about 3 feet away. This can be either a positive or a negative, depending on what you are trying to achieve. The shorter read range means that an interrogator located within a filing cabinet, or on a shelf, can locate tags within the vicinity, thereby making it easy to pinpoint a specific file’s location. However, the shorter read range means that files can sometimes be removed from a shelf and not be detected by a portal reader. These systems sometimes require workers to check out a file, by presenting it to an HF reader situated near an entrance or exit.
If the doorway into and out of the secure room is wider than 3 feet, and if you do not want to require that people remember to check out files, then an ultrahigh-frequency (UHF) system might be the best approach. A company known as FileTrail utilizes a UHF system. The 7th Judicial Circuit Court for Prince George’s County, in Maryland, uses the system to track files for 30,000 to 40,000 cases annually (see Maryland Court Tries UHF RFID File-Tracking System).
It might be worth talking to each of these companies, and to have them assess your facility, explaining to them how you would like the system to work. You could then make an informed judgment about which solution would best meet your particular needs.
—Mark Roberti, Founder and Editor, RFID Journal
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