Phone bugs are among the most popular of devices for surveillance. This is because there is something that humans enjoy about listening in on conversations and learning things that others may not want them to learn. For those who aspire to involve themselves in professional surveillance, and even for those who just participate in surveillance as a hobby, knowing the basics of phone bugs is valuable information.

Phone bugs are interesting because they are versatile. There are different types of these listening devices, and it is even possible to combine two or more different bugs into one bug that can act as its own backup device. These hybrid phone bugs are constructed from one of four different eavesdropping techniques: radio frequency (RF), ultrasonic, optical, and acoustic.

RF phone bugs are the most popular of covert listening devices. This is because they are inexpensive and they are difficult to trace. Even if the bug is discovered, chances are that it will not be traced to you. Radio waves are transmitted from the bug’s location to a secondary location. They are usually small and can easily be hidden in a device or very near the phone.

Ultrasonic phone bugs are bugs that read audio pressure waves. The signal from the talking is captured and then transformed into a signal too high for human ears to hear. It is transmitted to another location where it is turned back into an understandable signal. These bugs are harder to detect than RF bugs, and do cost a little more money.

The optical bug is the least popular of all the phone bugs. It is rather expensive and can be difficult to use. What the optical device does is turn sound (or even data, so it can be used to bug VoIP phone calls) into pulsating beams of light. The light is then reconverted into sound in order to be heard by the eavesdropper.

Finally, the last weapons in the covert listening devices arsenal are the acoustic phone bugs. These, however, are not technically bugs. They are merely low-tech options that allow you to listen in using things like rubber tubes at construction “soft spots” and open windows.

Know your listening devices, and you will be able to more effectively find out what you should know with phone bugs.