Several solutions have become known to prevent the unlawful appropriation of the goods introduced and offered for sale in the different shops. Among these there are the safety systems in the case of which the products intended to be protected are equipped with passive aerials, so-called goods protecting labels, made of metal foil, fixed on a paper or plastic carrier, and in the shop, practically near the exits, there are receiver-transmitter partial units radiating signals at a determined frequency. When these are in operation, if an active goods protecting label gets into the protected area, the safety system alarms with the help of sound and light effects, and prevents the goods from being taken out of the shop unlawfully.
Such devices are described in patent specifications No. EP 704.591 and FR 2.727 549.
However, in the case of products which are supplied for the shops in a cases, boxes or in some other packaging, there is the possibility of that the person intending to misappropriate the product tries the take it out of the selling place by leaving the packaging behind. Such products are, among other, tapes, CD-s or computer discs suitable for recording and storing audio and video signals.
Safety devices have also been developed for the protection of video, audio and other data carrying devices. The essence of these is that the goods, with their original packaging, are put in a case that can be locked, practically made of transparent material, also accommodating the packaging. The partial unit which activates the safety equipment is placed in the internal space of the safety device, next to the goods intended to be protected.
Such safety devices equipped with a storing space are described among others in patent specifications No. WO 92/08026, U.S. Pat. No. 5,147,034 and WO 97/16615, while information relating to signalling units which activate the different safety equipment is contained among others in patent specification No. WO/96241 19.
However, the defect of the known safety devices is that the separate signalling partial unit put in the internal space which accommodates the goods may be easily damaged in the course of putting the goods in the internal space and taking them out of there, and it may result in the failure of the alarm.
In the case of the signalling partial units connected to the protective case it is a problem that, especially in the case of the cases for the protection of the CD-s, the goods intended to be protected shades the signalling partial unit with radio-frequency, and so the partial unit is not able to emit signals of appropriate intensity and to turn on the safety device.
It must also be regarded as a disadvantage, that the manufacturing cost of the known signalling partial units put in the internal space of the protective case is relatively high, and it is still susceptible to breaking down.
It is also unfavourable that in the interest of reaching appropriate sensitivity the known signalling partial units are relatively spacious, and due to this in many cases they often cover information important for the customer on the packaging of the goods to be protected, and so their application may be a disturbing, purchase impeding factor.