This article relies largely or entirely on a single source. Relevant discussion may be found on the talk page. Please help improve this article by introducing citations to additional sources. Find sources: "Clear box" phreaking – news · newspapers · books · scholar · JSTOR(February 2024)
A clear box is an amplifier used by phreaks to use post-pay pay phones without paying. In some locations, especially rural areas in the United States and Canada, pay phones were configured for "post-pay" operation. In this mode, the handset microphone is muted until payment is made. The user of a post-pay pay phone would dial first, wait until the called party answered, and at that point the user would be prompted to insert the coins. Upon receiving the correct payment for the call, the pay phone would then connect the microphone and allow the caller to speak. An artifact of this scheme was that the called party usually heard the ACTS tones produced by the pay phone upon coin deposit.
The clear box circumvented the handset mute by providing the phreak with another microphone, whose output is amplified and fed into an induction coil. The induction coil is then placed on the pay phone's line or on its case near a sensitive circuit, introducing the caller's voice via induction and bypassing the muted handset.
Several text files on the subject of the clear box observe that some calls, such as to time and weather services and other information lines, do not require voice input from the caller. On post-pay phones, calls to such numbers were effectively free without the use of a clear box.
The clear box has become obsolete with the widespread conversion of post-pay phones to pre-pay operation.
"Clear box plans" - 1984 text file on the clear box
January 01, 1970
clear, phreaking, clear, redirects, here, subsystem, whose, internals, viewed, white, software, engineering, this, article, multiple, issues, please, help, improve, discuss, these, issues, talk, page, learn, when, remove, these, template, messages, this, artic. Clear box redirects here For a subsystem whose internals can be viewed see white box software engineering This article has multiple issues Please help improve it or discuss these issues on the talk page Learn how and when to remove these template messages This article relies largely or entirely on a single source Relevant discussion may be found on the talk page Please help improve this article by introducing citations to additional sources Find sources Clear box phreaking news newspapers books scholar JSTOR February 2024 This article includes a list of references related reading or external links but its sources remain unclear because it lacks inline citations Please help improve this article by introducing more precise citations February 2024 Learn how and when to remove this message Learn how and when to remove this message A clear box is an amplifier used by phreaks to use post pay pay phones without paying In some locations especially rural areas in the United States and Canada pay phones were configured for post pay operation In this mode the handset microphone is muted until payment is made The user of a post pay pay phone would dial first wait until the called party answered and at that point the user would be prompted to insert the coins Upon receiving the correct payment for the call the pay phone would then connect the microphone and allow the caller to speak An artifact of this scheme was that the called party usually heard the ACTS tones produced by the pay phone upon coin deposit The clear box circumvented the handset mute by providing the phreak with another microphone whose output is amplified and fed into an induction coil The induction coil is then placed on the pay phone s line or on its case near a sensitive circuit introducing the caller s voice via induction and bypassing the muted handset Several text files on the subject of the clear box observe that some calls such as to time and weather services and other information lines do not require voice input from the caller On post pay phones calls to such numbers were effectively free without the use of a clear box The clear box has become obsolete with the widespread conversion of post pay phones to pre pay operation See also editPhreaking boxesExternal links edit Clear box plans 1984 text file on the clear box Retrieved from https en wikipedia org w index php title Clear box phreaking amp oldid 1203325262, wikipedia, wiki, book, books, library,
