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# Blue Boxing Essay

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Now that you’ve stopped sending 2600Hz, several things happen:1) A trunk is seized.2) A “wink” is sent to the CALLING end from the CALLED end indicating thatthe CALLED end (trunk) is not ready to receive digits yet.3) A register is found and attached to the CALLED end of the trunk withinabout two seconds (max).4) A start-dial signal is sent to the CALLING end from the CALLED endindicating that the CALLED end is ready to receive digits.

Now, all of this is pretty much transparent to the blue boxer. All hereally hears when these four things happen is a . So,seizure of a trunk would go something like this:1> Send a 2600Hz2> Terminate 2600Hz after 1-2 secs.3> beepkerchunkOnce this happens, you are connected to a tandem that is ready to obey yourevery command. The next step is to send signalling information in order toplace your call. For this you must simulate the signalling used byoperators and automatic toll-dialing equipment for use on trunks. There aremainly two systems, DP and MF. However, DP went out with the dinosaurs, soI’ll only discuss MF signalling. MF (multi-frequency) signalling is thesignalling used by the majority of the inter- and intra-lata network. It isalso used in international dialing known as the CCITT no.5 system.MF signals consist of 7 frequecies, beginning with 700Hz and separated by200Hz. A different set of two of the 7 frequencies represent the digits 0thru 9, plus an additional 5 special keys. The frequencies and uses are asfollows:Frequencies (Hz) DomesticInt’l————————————- 700+900 11 700+110022 900+110033 700+130044 900+1300551100+130066 700+150077 900+1500881100+1500991300+150000 700+1700ST3p Code 1 900+1700STp Code 11100+1700KPKP11300+1700ST2p KP21500+1700STST The timing of all the MF signals is a nominal 60ms, except for KP, whichshould have a duration of 100ms. There should also be a 60ms silent periodbetween digits. This is very flexible however, and most Bell equipment willaccept outrageous timings. In addition to the standard useslisted above, MF pulsing also has expanded usages known as “expandedinband signalling” that include such things as coin collect, coin return,ringback, operator attached, and operator attached, and operatorreleased. KP2, code 11, and code 12 and the ST_ps (STart “primes” all havespecial uses which will be mentioned only briefly here.To complete a call using a blue box once seizure of a trunk has beenaccomplished by sending 2600Hz and pausing for the , onemust first send a KP. This readies the register for the digits that follow.For a standard domestic call, the KP would be followed by either 7 digits(if the call were in the same NPA as the seized trunk) or 10 digits (if thecall were not in the same NPA as the seized trunk). Exactly like dialingnormal fone call. Following either the KP and 7 or 10 digits, a STart issent to signify that no more digits follow. Example of a complete call:1> Dial 1-806-258-12342> wait for a call-progress indication (such as ring,busy,recording,etc.)3> Send 2600Hz for about 1 second.4> Wait for about ll-progress indication (such as ring,busy,recording,etc.)5> Send KP+305+994+9966+STThe call will then connect if everything was done properly. Note that if acall to an 806 number were being placed in the same situation, the are codewould be omitted and only KP + seven digits + ST would be sent.Code 11 and code 12 are used in international calling to requestcertain types of operators. KP2 is used in international calling to route acall other than by way of the normal route, whether for economic orequipment reasons. STp, ST2p, and ST3p (prime, two prime, and three prime)are used in TSPS signalling to indicate calling type of call (such ascoin-direct dialing.It all started here………………. Exodus

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