Radiozakladka – a device that transmits information via radio or acoustic signal from the telephone line. As such, the difference between them is not singular. The transmission distance is possible from 150 to 3000 meters. When using autonomous battery – Battery life is usually 3-4 days, there are types of beetles that feed directly from the phone line or network of 220 volts. It should be noted that, contrary to popular belief, radio transmitters devices may be difficult act of suppression and radio shumogeneratoram. When it comes to telephone radiozakladnom device, because it can be found all over the telephone line from the office to the city telephone exchange, the use of radio noise generators in the office makes no sense. To control the phone lines set up dozens of different devices, but none of them can not give 100% guarantee. Typically, to protect transmitted through telephone information use scramblers or encoders, but there is a disadvantage consisting in that the encryption device must be connected to all subscribers. In addition, to transfer information from your office can be used in any wire communications: cables fire alarm systems, cable television channels and the internal telephone subscriber communication Broadcasting Network and the network 220. The Wire is also possible through walls with windows using the so-called vibration sensors or radiostetoskopov. Hidden listening devices