Telephone Tap Detector

Telephone Tap Detector

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 actually "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.



Cloud, David S. and David Rogers. "Telecom Firms Lobby for Funding of Upgrades to Ease Surveillance." Wall Street Journal. (April 5, 2000): A4.

"How Secure Are Your Phone, Fax, Data Transmission Systems?" Security 34, no. 6 (June 1997): 75–76.

Kupperschmid, David. "James Bond 'Supplier' Has the Cure for Whatever Is Bugging You." Los Angeles Times. (April 26, 1985): 2.

"Texas Politicians' Cases Prompt New Interest in Eavesdropping." San Francisco Chronicle. (December 18, 1995): A12.


Domestic Intelligence
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Telephone Scrambler

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