Állományvédelmi kapu - Smartfreq RFID

Security gate

The purpose of the RFID security gate is to determine the status of items passing through it and, based on this, to trigger a possible (visual and/or acoustic) alarm event and record the events. Optionally, it may also be equipped with a people-counting (traffic-counting) function.

Because of the underlying technology, the asset-protection designs of HF and UHF systems differ from each other, but in both cases the specific item that triggers the alarm can be identified; it is not just a “general” alarm as with most retail anti-theft systems.

Technologies

HF

HF technológia sajátosságaiból adódóan a HF kapuk több egymással párhuzamos hurokantennából állnak, melyeket egy olvasó egység kapcsolgat időmultiplexelve.A leolvasás lassúsága miatt a kapuk többnyire előre beállított lopásvédelmi állapot (AFI és/vagy EAS) alapon offline riasztanak minden adott lopásvédelmi állapotú címkére, majd ezt követi a tag adattartmának kiolvasása, és továbbítása feldolgozásra, ami segítségével egy távoli gépen megállapítható a riasztást kiváltó példány azonosítója, amiből egy további IKR felé intézett SIP2 lekérdezéssel megkaphatók a példány könyvtári rendszerben tárolt adatai is. HF tartományban csak egyetlen frekvencisáv van ezért a több nagy teljesítménnyel működő közeli (8-10méteren belüli) kapu csak megfelelő szinkronizálással használható, ami tovább csökkenti a leolvasás sebességét, viszont egy olvasóra multiplexerrel több antenna is kapcsolható égy összességében nagyon széles átjáró is lefedhető egymástól kb. 120cm-re levő elemekkel.

UHF

In UHF technology, the relative positioning and number of antennas are less constrained, making it possible to implement custom gate designs, including configurations with both lower and upper antenna placement. The reading speed is very high, so it is possible to read all items passing through the gate; however, offline alarming based on the tag’s data content is also supported. In this respect, similarly to HF systems, alarms can be triggered without an ILS query and even without dedicated software. That said, solutions based on querying the library system are more widespread, as they allow operation even in cases where circulation is performed using barcodes.
UHF rendszereknél Európában alapvetően két külön frekvenciatartomány használható, és mindegyiken belül több részsáv van, így UHF olvasóknál nincs szükség az egy helyen működő olvasók szinkronizálására.

The reading field of HF security gates, due to the nature of the magnetic field generated by the loop antennas, can be more precisely confined than in the case of UHF, where the radiated electromagnetic waves may be reflected by various surfaces. To mitigate this, gates can be built with shielding and reflective materials and with high-gain directional antennas, which significantly reduce distant false reads; additionally, distant, non-moving tags can also be filtered based on the phase and received signal strength measured at the reader.
The operation of HF gates is affected not only by other high-power HF readers operating nearby, but also by metal surfaces. While UHF antennas can be installed directly on metal surfaces, HF antennas—depending on the size and extent of the metal surface—may need to be placed at a distance of more than half a meter to ensure that the proper field lines can form within the gate without being significantly influenced by the metal.
Both technologies can be circumvented with sufficient expertise. Although HF tags are less affected by the human body than UHF tags, holding the antenna of a tag of any technology in a particular way can detune it to such an extent that the gate does not detect it. This can be achieved even more easily using various metal surfaces, for example in a laptop bag; however, from this perspective, a UHF tag becomes readable again at a much smaller distance from metal.
An additional use of security gates is traffic counting; this is typically performed using the same sensor that activates the operation of the gates.
They can be integrated with the Smartfreq statistics page, where the operation of the devices, their alarms, and traffic-counting data can be queried as desired.