MDE-3664B TRIND® Start-up, Service, and Parts Manual · June 2013
Page A-9
Wireless Communication and Air Interface
Appendix A - Radio Frequency Identification Defined
Devices characterized by data storage capacities up to 128 bits are sufficient to hold a serial or
identification number together, possibly, with parity check bits. Such devices may be
manufacturer or user programmable. Tags with data storage capacities up to 512 bits, are
invariably user programmable, and suitable for accommodating identification and other
specific data such as serial numbers, package content, key process instructions or possibly
results of earlier interrogation/response transactions.
Tags characterized by data storage capacities of around 64 kilobyte may be regarded as
carriers for portable data files. With increased capacity the facility can also be provided for
organizing data into fields or pages that may be selectively interrogated during the reading
process.
Data Read Rate
It has already been mentioned that data transfer rate is essentially linked to carrier frequency.
The higher the frequency, generally speaking, the higher the transfer rates. It should also be
appreciated that reading or transferring the data requires a finite period of time, even if rated in
milliseconds, and can be an important consideration in applications where a tag is passing
swiftly through an interrogation or read zone.
Data Programming Options
Depending upon the type of memory a tag contains, the data carried may be Read-only, Write
Once Read Many (WORM) or read/write. Read-only tags are invariably low capacity devices
programmed at source, usually with an identification number. WORM devices are user
programmable devices. Read/write devices are also user-programmable but allowing the user
to change data stored in a tag. Portable programmers may be recognized that also allow
in-field programming of the tag while attached to the item being identified or accompanied.
Physical Form
RFID tags come in a wide variety of physical forms, shapes sizes and protective housings.
Animal tracking tags, inserted beneath the skin, can be as small as a pencil lead in diameter
and ten millimeters in length. Tags can be screw-shaped to identify trees or wooden items, or
credit card shaped for use in access applications. The anti-theft hard plastic tags attached to
merchandise in stores are also RFID tags, as are heavy-duty 120X100X50 mm rectangular
transponders used to track inter-modal containers, or heavy machinery, trucks, and railroad
cars for maintenance and tracking applications.