We describe a simple wiretapping system that does not require any connection to the line. To operate the system, simply bring the pickup coil X1 close to the line, thus capturing the signals. This coil is the so-called “maricota” used by radio amateurs to connect the line to transmitters. It can also be obtained from old phones and alarm clocks. In the circuit, the coil excites a pre-amplifier transistor that powers an audio amplifier of the type TBA820.
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