Telephone Tap Detector
Telephone tap detector (Forensic Science)
Wiretapping is the accessing of telephone conversations by direct interception of the telephone signal. Historically, wiretap laws in the United States were designed to protect the content of telephone conversations. Initiating a telephone wiretap required a court order and a high level of proof that the wiretap was essential to a law-enforcement investigation. The Patriot Act, which was passed following the 2001 terrorist attacks on the Pentagon and on the World Trade Center in New York City, made it easier for law-enforcement agencies in the United States to tap telephones. All the Patriot Act requires is that the requesting agency certify that information likely to be obtained from the tap is relevant to an investigation.
Traditional telephone tap detectors are devices that, when spliced into telephone lines, indicate when the voltage on the lines changes. When a tap detector is installed, it is set to monitor the voltage on the line when it is assumed to be untapped. If a physical tap is placed on the line, the voltage will decrease. Other events, such as listening in on a phone extension, will also cause the voltage to decrease. Changes in telephone transmission and telephone tapping technologies have, however, rendered traditional telephone tap detectors almost useless against all but the crudest types of taps. Despite this, some electronics retailers continue to sell voltage-change telephone tap detectors.
Changes in telephone...
(The entire section is 413 words.)
Further Reading (Forensic Science)
Telephone Tap Detector (World of Forensic Science)
Telephone conversations can be monitored and recorded. Law enforcement personnel may even, with court permission, tap a phone to acquire information that can potentially be useful in a prosecution. But technology can also thwart this effort. When a telephone tap is suspected, an individual can acquire technology to detect the monitoring device.
A telephone tap detector aids communication security by providing electronic recognition of attempts to intercept a call through wiretapping or listening devices. Telephone tapping is, at least in certain particulars, an exact science, and tap detection technology must likewise be efficient to counteract those efforts. With telephone tapping no longer an extremely infrequent aspect of daily life, tap detectors have become a popular item among security-conscious consumers.
In tapping into a phone line, surveillance personnel use technology akin to that which an electrician might apply in attempting to siphon power from an electric line. However, whereas an electric wire attached to a circuit receives a regular supply of power, a telephone tap cannot maintain constant access to a telephone line, or it would be too easy to detect. Instead, the tap "seizes" the telephone line as a call is coming in.
The tap is most likely to engage between the first and third ring of an incoming call, and from that point onward, assuming all conditions are reasonably favorable for surveillance, the tap remains in effect for the duration of the call. A telephone tap detector recognizes this seizure of the phone line, and provides further verification once the call concludes. Depending on the number and timing of disconnection reactions after the receiver is reengaged, a good tap detector (consumer models sell for several hundred dollars) can determine whether wiretapping equipment is in the process of disengaging from the phone line.
SEE ALSO Telephone caller identification (caller ID).