Security monitoring system and method

DETAILED DESCRIPTION Referring first to FIG.
1, there is shown a radio tag device constructed in accordance with the present invention.
The device is an assembly that consists of radio tag circuitry indicated generally at 120 that is positioned on and affixed to a substrate 160.
Substrate 160 is, in turn, sandwiched between a soft opaque plastic layer 110 and a backing layer 170.
Each portion of this composite construction will be discussed in turn.
As shown in FIG.
1, a typical arrangement for radio tag circuitry 120 includes an antenna 140, radio frequency circuits 130, logic and other control circuits 131, memory 132, etc.
As contemplated by the present invention, radio tag circuitry 120 represents a passive device that needs no source of energy.
Rather, it can be both read and written by a remotely generated radio signal.
Different radio tags can be distinguished from each other in the read and/or write process, since each may have a unique identification code that can be read.
Memory 132 can be used to store various information used in communicating with the radio tag.
This information can include the date of the last reading or the last successful operation of the radio tag.
The information that is transmitted to the radio tag can be stored in the memory and later can, upon a subsequent query, be read out of memory 132 and transmitted to a remote monitoring device or location.
As stated previously, the specific arrangement of radio tag circuitry 120 can vary, as long as the functionality described in U.
S.
Pat.
No.
5,528,222 issued to Moskowitz et.
al, or in the Gemplus report, both of which are discussed above, is achieved.
Substrate 160 can be made of a layer of thin, rigid material such as a ceramic material, that is breakable when flexed or bent.
Radio tag circuitry 120 is affixed to the surface of substrate 160, such as by epoxy or other adhesive, so that removal or tampering is difficult or impossible.
The individual positions of the different elements of circuitry 120 on substrate 160 may, of course, vary with each radio tag design, so that the arrangement shown in FIG