114 lines
7.1 KiB
Plaintext
114 lines
7.1 KiB
Plaintext
MONEY INCORPORATED DIGEST #8
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RELEASED 27 FEB 1994
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TODAY'S TOPIC: SWITCHING FOR IMBECILES!
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MONEY INC. IS: SLEEPY SONIC FURY tHe BiG cH33s3 METHOD MAN
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Well, lets assume you're an idiot...a dolt...an imbecile...a simpleton...you get the
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idea. Well, you want to be a hack/phreak d00d, and don't know jack shit about the fone
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company. Well, you could do one of two things....the library has a good
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kindergarten-level book called "What Happens When You Maka A Fone Call." This could
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get you started, but since you want to be K-Rad 3133+, you gotta get something more.
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Well here it is....the Money Incorporated Elementary Switching Guide....most of it's
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plagrarized from an article in the Winter 94 issue of 2600, so if you have the issue,
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read this anyway...I didn't waste good time writing it for you to delete the file!
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Signals are sent over the telefone network to control its operation and indicate its
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status. Signalling is essential to the internal coordination of transmission and
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switching facilities. It also allows the user to submit requests to the network and
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allows the network to provide the user (abuser) interpretable responses.
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At the begininning of time, human beings employed at the local telco office watched
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for flashing lamps on their consoles to learn that someone wanted to make a call. The
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flashing was intiated by your Great Aunt Bertha turning a crank on her telefone (I
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bet.) The operator plugged her headest into Bertha's jack (bet that hurt) and
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determined through verbal interaction what number Bertha wanted to call. If the
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reciving party's lamp was unlit, the operator rang the recieving party's fone and
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connected Bertha's jack to the recieving party's. If the recieving line was busy, the
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operator told Bertha to fuck off and try back later.
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If the recieving party was served by another exchange, the operator called an
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operator at the distant exchange through an interoffice trunk, and told her the number
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of the recieving party. If the recieving party's lamp was unlit the distant operator
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rang the reciever's fone, and retuned to her donuts and coffee.
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More recently the request for service is made by simply lifting that handset off the
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fone, closing a 48 volt DC circuit. The flow of current is interpreted by the switch
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at the central office as a request for service. This current carries two concurrent
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sine waves, one 350Hz and one 440Hz, which produce a cool sound in the earpiece, often
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called the "dial tone." The flow of DC contiues as long as the fone is off the hook,
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and the switching facility uses this information,, specifically, in determining whether
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the line is still in use.
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The number of the party to be called is conveyed to the switch by the caller with
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either tones or pulses. The early telefone was equipped with a spring loaded rotating
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dial, which had numbered "finger-holes." After tha caller spun the disk until blocked
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by a stationary "finger stop," the disk would interrupt the DC flow as many times as
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the nukber dialed (except for 10 times for the 0.) If the number dialed was 4, as the
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disk rewound, the DC circuit would be broken four times for about 6/100 of a seconf and
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restored between each break for 4/100 of a second. Each pulse cycle took about 1/10 of
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a second (for those of you who can't add.) Newer non-rotary fones, capable of pulse
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dialing do this by interrupting the circuit with an electronic control. Nimble
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fingers can also do this by quickly hitting the hang-up button.
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More modern fones emit a pair of concurrent sine waves to communicate numbers to the
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switch. On a standard dial pad each button on the top row (1,2,3) emit 697Hz; second
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row, 770Hz; third row 852Hz; and fourth row (*,0, and #) 941Hz. The buttons in the
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first column (1,4,7,*) emit 1209Hz; scond column, 1336Hz; thrid column (3,6,9,#)
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1447Hz. These tone pairs are interpreted by the switching facility as the number
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pressed on the dial pad. Although ancinet switches cannot interpret tones, new (all)
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switches interpret pulses (for those old farts who refuse to get rid of the fone they
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used in 1946.)
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The central office provides callers with an aural representation of the recieving
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party's fone in the act of ringing with a simutaneous pair of tones called "ringback."
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They are 440Hz and 480Hz, and bleep for two of each six seconds while the distant fone
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is ringing. (Ok, how many of you thought the sound was the actual fone on the other
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end ringing?)
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The famous "line-busy" signal is comprised of simultaneous 480Hz and 620Hz tones,
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bleeping one half of each second until the caller hangs up. The "trunk-busy" or
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"reorder" signal is issued when switching or transmission facilities are unable to
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handle the call. It is identical to the lin-busy signal but twice the rate.
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When all goes well, the recieving party's fone is sent a ringing signal, not audible
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at the earpiece, but inciting a bell, chirping sounds, or even flashing lights. The is
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accomplished by a 20Hz signal fo about 74 volts, issued for two of each six seconds
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until the ringing fone is picked up or the calling fone is hung up.
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A call to a party served by a central office other than one's own requires the use
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of one of more interoffice trunks. Older long distance lines used a 2600Hz signal when
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the trunk was available. When the switch began using the trunk, the caller's central
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office ceased issuance of the tone. The distant offce was alerted of the incoming call
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by this change.
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More recently, (unfortunately) interoffice signalling has been moved from voice
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lines to a seperate dedicated line. A single data circuit can control thousands of
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voice circuits, conveying telefone number, trunk availability, and other information.
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Line busy signals are no longer sent from the distant office. A data signal is sent
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via the signal circuit, initiating the generation of the audible signal at the caller's
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office. Previously, sending an audio signal from the distant office required the use
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of a voice circuit, which is now left free for other users' conversation (but making
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blue boxing impossible.)
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The caller's telefone number is also conveyed through the sperate circuit. The
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distant office knows the caller's number, and the recieving party may also get it
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(ugh!) It is sent to the recieving party's equipment as a shot burst of digital data,
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encrypted by phase shift keying. The reciever's equipment must decrypt the sigal, and
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display it or otherwise act on it. Depending on the number, the call may be
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automatically rejected, prventing the fone from ringing, or it may be forwarded to
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another location.
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Well, hopefully this short article has enlightened some of you lamerz out there. If
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you didn't understand part of it, the go kill yourself, because you don't deserve to
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live. If you already know this shit, the congratulations, you've just wasted credits
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to downlad this. Hopefully, I have enlightened at least one person and saved him from
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the clutches of ignorance. But then again, maybe not.
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Copyright 1994 MONEY INCORPORATED
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ALL RIGHTS MOLESTED BY MICHAEL JACKSON
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MONEY INCORPORATED IS: SLEEPY SONIC FURY THE BIG CH33S3 METHOD MAN
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