26-09-2016, 03:59 PM
Phreaking is a slang term coined to describe the activity of a culture of people who study, experiment with, or explore, telecommunication systems, such as equipment and systems connected to public telephone networks. The term phreak is a sensational spelling of the word freak with the ph- from phone, and may also refer to the use of various audio frequencies to manipulate a phone system. Phreak, phreaker, or phone phreak are names used for and by individuals who participate in phreaking.
The term first referred to groups who had reverse engineered the system of tones used to route long-distance calls. By re-creating these tones, phreaks could switch calls from the phone handset, allowing free calls to be made around the world. To ease the creation of these tones, electronic tone generators known as blue boxes became a staple of the phreaker community, including future Apple Inc. cofounders Steve Jobs and Steve Wozniak.
The blue box era came to an end with the ever increasing use of computerized phone systems, which sent dialing information on a separate, inaccessible channel. By the 1980s, much of the system in the US and Western Europe had been converted. Phreaking has since become closely linked with computer hacking.[1] This is sometimes called the H/P culture (with H standing for hacking and P standing for phreaking).
Phone phreaking got its start in the late 1950s in the United States. Its golden age was the late 1960s and early 1970s. Phone phreaks spent a lot of time dialing around the telephone network to understand how the phone system worked, engaging in activities such as listening to the pattern of tones to figure out how calls were routed, reading obscure telephone company technical journals, learning how to impersonate operators and other telephone company personnel, digging through telephone company trash bins to find "secret" documents, sneaking into telephone company buildings at night and wiring up their own telephones, building electronic devices called blue boxes, black boxes, and red boxes to help them explore the network and make free phone calls, hanging out on early conference call circuits and "loop arounds" to communicate with one another and writing their own newsletters to spread information.
Prior to 1984, long-distance telephone calls were a premium item, with archaic regulations. In some locations, calling across the street counted as long distance. To report that a phone call was long distance meant an elevated importance universally accepted because the calling party is paying by the minute to speak to the called party; transact business quickly.
Phreaking consisted of techniques to evade the long-distance charges. This evasion was illegal; the crime was called "toll fraud."
Switch hook and tone dialer
Possibly one of the first phreaking methods was switch-hooking, which allows placing calls from a phone where the rotary dial or keypad has been disabled by a key lock or other means to prevent unauthorized calls from that phone. It is done by rapidly pressing and releasing the switch hook to open and close the subscriber circuit, simulating the pulses generated by the rotary dial. Even most current telephone exchanges support this method, as they need to be backward compatible with old subscriber hardware.
By rapidly clicking the hook for a variable number of times at roughly 5 to 10 clicks per second, separated by intervals of roughly one second, the caller can dial numbers as if they were using the rotary dial. The pulse counter in the exchange counts the pulses or clicks and interprets them in two possible ways. Depending on continent and country, one click with a following interval can be either "one" or "zero" and subsequent clicks before the interval are additively counted. This renders ten consecutive clicks being either "zero" or "nine", respectively. Some exchanges allow using additional clicks for special controls, but numbers 0–9 now fall in one of these two standards. One special code, "flash", is a very short single click, possible but hard to simulate. Back in the day of rotary dial, very often technically identical phone sets were marketed in multiple areas of the world, only with plugs matched by country and the dials being bezeled with the local standard numbers.[citation needed]
Such key-locked telephones, if wired to a modern DTMF capable exchange, can also be exploited by a tone dialer that generates the DTMF tones used by modern keypad units. These signals are now very uniformly standardized worldwide, and along with rotary dialing, they are almost all that is left of in-band signaling. It is notable that the two methods can be combined: Even if the exchange does not support DTMF, the key lock can be circumvented by switch-hooking, and the tone dialer can be then used to operate automated DTMF controlled services that can't be used with rotary dial.
The term first referred to groups who had reverse engineered the system of tones used to route long-distance calls. By re-creating these tones, phreaks could switch calls from the phone handset, allowing free calls to be made around the world. To ease the creation of these tones, electronic tone generators known as blue boxes became a staple of the phreaker community, including future Apple Inc. cofounders Steve Jobs and Steve Wozniak.
The blue box era came to an end with the ever increasing use of computerized phone systems, which sent dialing information on a separate, inaccessible channel. By the 1980s, much of the system in the US and Western Europe had been converted. Phreaking has since become closely linked with computer hacking.[1] This is sometimes called the H/P culture (with H standing for hacking and P standing for phreaking).
Phone phreaking got its start in the late 1950s in the United States. Its golden age was the late 1960s and early 1970s. Phone phreaks spent a lot of time dialing around the telephone network to understand how the phone system worked, engaging in activities such as listening to the pattern of tones to figure out how calls were routed, reading obscure telephone company technical journals, learning how to impersonate operators and other telephone company personnel, digging through telephone company trash bins to find "secret" documents, sneaking into telephone company buildings at night and wiring up their own telephones, building electronic devices called blue boxes, black boxes, and red boxes to help them explore the network and make free phone calls, hanging out on early conference call circuits and "loop arounds" to communicate with one another and writing their own newsletters to spread information.
Prior to 1984, long-distance telephone calls were a premium item, with archaic regulations. In some locations, calling across the street counted as long distance. To report that a phone call was long distance meant an elevated importance universally accepted because the calling party is paying by the minute to speak to the called party; transact business quickly.
Phreaking consisted of techniques to evade the long-distance charges. This evasion was illegal; the crime was called "toll fraud."
Switch hook and tone dialer
Possibly one of the first phreaking methods was switch-hooking, which allows placing calls from a phone where the rotary dial or keypad has been disabled by a key lock or other means to prevent unauthorized calls from that phone. It is done by rapidly pressing and releasing the switch hook to open and close the subscriber circuit, simulating the pulses generated by the rotary dial. Even most current telephone exchanges support this method, as they need to be backward compatible with old subscriber hardware.
By rapidly clicking the hook for a variable number of times at roughly 5 to 10 clicks per second, separated by intervals of roughly one second, the caller can dial numbers as if they were using the rotary dial. The pulse counter in the exchange counts the pulses or clicks and interprets them in two possible ways. Depending on continent and country, one click with a following interval can be either "one" or "zero" and subsequent clicks before the interval are additively counted. This renders ten consecutive clicks being either "zero" or "nine", respectively. Some exchanges allow using additional clicks for special controls, but numbers 0–9 now fall in one of these two standards. One special code, "flash", is a very short single click, possible but hard to simulate. Back in the day of rotary dial, very often technically identical phone sets were marketed in multiple areas of the world, only with plugs matched by country and the dials being bezeled with the local standard numbers.[citation needed]
Such key-locked telephones, if wired to a modern DTMF capable exchange, can also be exploited by a tone dialer that generates the DTMF tones used by modern keypad units. These signals are now very uniformly standardized worldwide, and along with rotary dialing, they are almost all that is left of in-band signaling. It is notable that the two methods can be combined: Even if the exchange does not support DTMF, the key lock can be circumvented by switch-hooking, and the tone dialer can be then used to operate automated DTMF controlled services that can't be used with rotary dial.
