| 摘要 |
A anti-theft security system and process for securing merchandise. The security system comprises a base station that has a low frequency (LF) stage having a LF receiving and transmitting unit attached to the base station. Attached to the LF stage is an antenna for generating an electromagnetic field. In addition a plurality of merchandise security labels are each attached to a piece of merchandise. Each security label comprises a LF stage having a LF transmitter and receiving unit operating on the same frequency as the base station LF stage. When a security label enters the field transmission region of the base station the base station a bidirectional signal transmission takes place between the base station and at least one of the security label transponders. If the base station detects an active LF stage on the one of the security labels then an alarm will sound. The process for securing this merchandise includes the steps of transmitting a control signal of the same frequency from a LP stage of the base station to a LF stage on a transponder and back. In addition, the base station transmits a receive confirmation signal to the transponder and the transponder sends this signal back again. Finally check mechanisms are integrated into the transmission sequence so that an alarm is triggered if the defined criteria are not maintained or satisfied.
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