Wireless video transmission systems
Wireless video transmission systems are used to transmit video and audio signals. In the private sector, for example, a receiving device such as a satellite receiver can establish a connection to a screen in another room.
In video surveillance, the signals from one or more video cameras are often transmitted to monitors and recording devices. The cameras often contain microphones for acoustic monitoring.
Existing systems mostly work in the ISM band and are approved for free use in Germany by the Federal Network Agency . ISM systems must be viewed as public because the signals can be received freely. They differ from closed circuit television systems (CCTV) in the narrower sense, which are only accessible to a closed group of users (authorities, internal use in companies).
As an alternative to the traditional systems are now often wireless - radio networks for transmitting video signals from network cameras used for other network-enabled devices.
Technical aspects
The transmission takes place in the ISM band at 2.4 GHz in the decimeter wave range . This enables short transmission routes. Because of the short wavelength , short linear antennas or directional antenna systems can be used. The Federal Network Agency has released the ISM band at 2.4 GHz for video transmission for private and commercial use. The signals must not be technically encrypted.
The video signals are usually transmitted with analog frequency modulation. PAL or NTSC is used as the video transmission format.
Data protection issues and privacy protection
Since the ISM band in Germany is open to all user groups, anyone can purchase and operate transmitting and receiving devices for this area. Due to the relatively weak transmission power and the physical properties of the ISM band, interference with other ISM applications rarely occurs . The signals can be received in the immediate vicinity of the transmitter with a receiver for the ISM band. This reception is legal.
An NDR magazine showed in January 2010 that it is possible for anyone interested to receive ISM surveillance cameras without great technical effort. During the research, free-to-air cameras (including sound transmission) were found in pharmacies. The eavesdropping (also visually) of customer conversations represented a considerable encroachment on personal rights. There are also considerable problems in data protection .
The Schleswig-Holstein data protection center then emphasized that meaningful signs with text or pictograms that refer to the recording must be installed in every area monitored by ISM systems. The signs must be large enough and placed at eye level.
See also
Web links
- Information from the Schleswig-Holstein data protection officer on video surveillance and webcams (PDF; 167 kB)
Individual evidence
- ↑ Information from the Schleswig-Holstein data protection officer on video surveillance and webcams ( memento of the original dated November 2, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . On: datenschutzzentrum.de, PDF, p. 10.
