One of the ways that eavesdropping devices can be used is for monitoring telephone communication taking place on either landlines or mobiles. This practice is known as telephone tapping or wiretapping. In this article we will focus on the different eavesdropping devices that are commonly used on landlines, however you should be aware that cell phone monitoring is also a serious threat.
Official wiretapping may be difficult if not impossible to detect since this is usually carried out digitally at the exchange and there are no intrusive eavesdropping devices involved. Unofficial wiretapping can be accomplished in a number of ways using eavesdropping devices that transmit or record both sides of the conversation and which can be purchased for as little as a few dollars.
It pays to be aware that conversations held over the phone may not be as private as you think, and you should approach any call with the attitude that everything you say could be being recorded via an eavesdropping device. In-ear telephone recording microphones are basic eavesdropping devices that can be used on any landline, cordless phone or mobile. Virtually anyone could operate an eavesdropping device like this, since the microphone is simply held in place against the receiver using an ear bud and attaches to a mini recorder that will clearly and silently capture every word both parties say.
Direct line wiretaps are eavesdropping devices that form a physical intrusion into the telephone line in or near your house. These sorts of eavesdropping devices are capable of calling the listener on a preprogrammed number whenever the phone is activated. Both sides of the conversation can be heard distinctly through the direct line eavesdropping device no matter how far away the listener might be from the target. Phone tap eavesdropping devices can sometimes cause voltage losses, noises on the line or volume changes. Certain bug detectors are designed to detect these eavesdropping devices by monitoring your line for minute signal variations, and they can also alert you if somebody is listening in on another extension.
Telephone pick up coils are another kind of eavesdropping device that are used for phone tapping. They are usually attached to the base of the phone or the back of the handset and are a most effective phone tap eavesdropping device since they gain the signal inductively. Inductive eavesdropping devices are difficult to detect with wiretap bug detectors because they are not physically attached to the line and there is no associated voltage drain.
Another kind of wiretap eavesdropping device is a radio transmitter that attaches to a phone line either inside or outside of the building. Radio wiretap eavesdropping devices use the phone line for a power source and antenna, and transmit a signal which can be picked up on an FM receiver within a radius of up to ten kilometers. These kinds of eavesdropping devices only transmit when a call is in progress, but could be picked up with a bug detector radio frequency sweep when active.
It is worthwhile remembering that even when your telephone handset is not in use, the microphone in it can still be used as an eavesdropping device. Hook switch bypasses and infinity transmitters are phone modifications that can turn your handset into an eavesdropping device that will provide clear audio surveillance of conversations happening within 10 metres of the telephone.