Encrypted UHF room-telephone digital audio transmitter

UHF audio transmitter with double room-telephone listening function. Equipped with spectrum inversion encoding for transmission security!

This digital audio transmitter is used both for wiretapping and room monitoring, and transmission of audio information through a crystal controlled radio channel. The micro-transmitter is a compact module, equipped with external antenna, microphone and flexible wires to connect it to the telephone line. Also equipped with the encryption method called Spectrum Inversion to protect the transmitted data against any possible interception. Connection is done by tearing open one of the wires of a standard analog telephone line; the line is also used as a power supply.

The transmitter can automatically switch between room and telephone monitoring modes. While the phone handset is hung up, the transmitter remains in room monitoring mode. As soon as the handset is picked up, the transmitter would automatically switch to the telephone monitoring mode.