A security system for protecting articles (8), the system comprising at
least one Electronic Article Surveillance (EAS) loop (1) , one Emitting
Unit (7) and one Detecting Unit (9) attached to each article (8)
to be protected, the Detecting Unit (9) having a detector to detect electromagnetic
fields emitted by the EAS loop (4) and the Emitting Unit (7) and
to distinguish between them, and an alarm generator for generating an alarm if
a predetermined sequence of fields is detected. The system combines existing EAS
loops (4) normally present in a retail store with Emitting Units (7)
and Detecting Units (9) so as to monitor movement of articles (8),
especially supermarket trolleys, around the retail store.
