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A blue box is an electronic device that generates the same tones employed by a telephone operator's dialing console to switch long-distance calls. A blue box is a tool that emerged in the 1960s and '70s; it allowed users to route their own calls by emulating the in-band signaling mechanism that then controlled switching in long distance dialing systems. The most typical use of a blue box was to place free telephone calls. A related device, the black box enabled one to receive calls which were free to the caller. The blue box no longer works in most Western nations, as modern switching systems do not use in-band signaling. Instead, signaling occurs on an out-of-band channel which cannot be accessed from the line the caller is using, a system called Common Channel Interoffice Signaling or CCIS. ==History== In November 1954, the ''Bell System Technical Journal'' published an article titled "In-Band Single-Frequency Signaling" which described the process used for routing telephone calls over trunk lines with the then-current signaling system, R1. The article described the basics of the inter-office trunking system and the signalling used. This, while handy, could not be used in and of itself, as the frequencies used for the Multi-Frequency, or "MF", tones were not published in this article. In November, 1960, the other half of the equation was revealed by the Bell System Technical Journal: another article titled "Signaling Systems for Control of Telephone Switching" was published containing the frequencies used for the digits that were used for the actual routing codes With these two items of information, the phone system was at the disposal of anyone with a cursory knowledge of electronics. Once Bell realized what they had done, company representatives visited most college campuses and physically cut out the pages that had the tone frequencies, but the information had already been made public and the error was irreversible. However, contrary to numerous stories, before finding the articles in the Bell System Technical Journal it was discovered by many, some very unintentionally and to their annoyance, that a 2600 Hz tone, used by AT&T Corporation as a steady signal to mark currently unused long-distance telephone lines, or "trunk lines", would reset those lines. Joe Engressia (known as Joybubbles) accidentally discovered it at the age of 7 by whistling (with his mouth). He and other famous phone phreaks such as "Bill from New York" and "The Glitch", trained themselves to whistle 2600 Hz to reset a trunk line. They also learned how to route phone calls by At one point in the 1960s, packets of the Cap'n Crunch breakfast cereal included a free gift: a small whistle that (by coincidence) generated a 2600 Hz tone when one of the whistle's two holes was covered. The phreaker John Draper adopted his nickname "Captain Crunch" from this whistle. Others would utilize exotic birds such as canaries which are able to hit the 2600 Hz tone to the same effect. With the ability to blue box, what was once individuals exploring the telephone network started to develop into a whole sub-culture. Famous phone phreaks such as John "Captain Crunch" Draper, Mark Bernay, and Al Bernay used blue boxes to explore the various 'hidden codes' that were not dialable from a regular phone line. Some of the more famous pranksters were Steve Wozniak and Steve Jobs, founders of Apple Computer. On one occasion Wozniak dialed Vatican City and identified himself as Henry Kissinger (imitating Kissinger's German accent) and asked to speak to the Pope (who was sleeping at the time). Wozniak said in 1986: Blue boxes were primarily the domain of "pranksters" and "explorers", but others used blue boxes solely to make free phone calls. They were also popular with drug dealers and other criminals, because calls were not only free, but were virtually impossible to trace with the technology available at the time. Blue boxing hit the mainstream media when an article by Ron Rosenbaum titled ''Secrets of the Little Blue Box'' was published in the October 1971 issue of ''Esquire'' magazine.〔 Suddenly, many more people wanted to get into the phone phreaking culture spawned by the blue box, and it furthered the fame of Captain Crunch. Two major amateur radio magazines ('73' and "CQ') published articles on the telephone system in the mid 1970s. CQ Magazine also published details on phone phreaking, including the tone frequencies and several working blue box schematics in 1974. In November 1988, the CCITT (now known as ITU-T) published recommendation Q.140, which goes over Signaling System No. 5's international functions, once again giving away the 'secret' frequencies of the system. This caused a resurgence of blue boxing incidents with a new generation. During the early 1990s, blue boxing became popular with the international warez scene, especially in Europe. Software was made to facilitate blue boxing using a computer to generate the signalling tones and play them into the phone. For the PC there were BlueBEEP, TLO, and others, and blue boxes for other platforms such as Amiga were available as well. In the 1970s and 80s some trunks were modified to filter out single frequency tones arriving from a caller. The death of blueboxing came in the mid to late 1990s when telcos, becoming aware of the problem, eventually moved to out-of-band signaling systems with separate data and signalling channels (such as CCIS and SS7). These systems separated the voice and signaling channels, making it impossible to generate signalling signals from an ordinary voice phone line. It is rumored that some international trunks still utilize in-band signaling and are susceptible to tones, although often it's 2600+2400 Hz then 2400 Hz to seize. Sometimes the initial tone is a composition of three frequencies. A given country may have inband signalling on trunks from a specific country but not others. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「blue box」の詳細全文を読む スポンサード リンク
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