Wireless Telephone Line Spy Circuit

Here’s a design of a phone bug circuit. This wireless telephone line spy circuit can be used to transmit the phone conversation to a nearby FM radio. This circuit must connected to a normal phone line. This is the figure of the circuit;

The first transistor is turned off, if the voltage drops to less than 15v (if the telephone line is in use). It will enable the second transistor to oscillate at approx 100MHz. Then transmit the phone conversation to a nearby FM radio.

Phone Incoming Call Flasher Circuit

Here’s a design circuit of phone message flasher, an alternative way to get alarmed when there is an incoming call. This is the figure of the circuit;

When the phone rings, high line voltage will be detected by A differential amplifier with hysteresis (Q2, Q3, and Q1). This action will turn on multi vibrator Q5/Q6, Q4. The LED will flashed via Q7. When the phone line voltage drops to less then 9V, the Q2 and Q1 will be turned off, which indicates an off hook condition.