MONEY INCORPORATED DIGEST #8
RELEASED 27 FEB 1994
TODAY'S TOPIC: SWITCHING FOR IMBECILES!

MONEY INC. IS:  SLEEPY  SONIC FURY  tHe BiG cH33s3  METHOD MAN

   Well, lets assume you're an idiot...a dolt...an imbecile...a simpleton...you get the
idea.  Well, you want to be a hack/phreak d00d, and don't know jack shit about the fone
company.  Well, you could do one of two things....the library has a good
kindergarten-level book called "What Happens When You Maka A Fone Call."  This could
get you started, but since you want to be K-Rad 3133+, you gotta get something more.
Well here it is....the Money Incorporated Elementary Switching Guide....most of it's
plagrarized from an article in the Winter 94 issue of 2600, so if you have the issue,
read this anyway...I didn't waste good time writing it for you to delete the file!

   Signals are sent over the telefone network to control its operation and indicate its
status.  Signalling is essential to the internal coordination of transmission and
switching facilities.  It also allows the user to submit requests to the network and
allows the network to provide the user (abuser) interpretable responses.

   At the begininning of time, human beings employed at the local telco office watched
for flashing lamps on their consoles to learn that someone wanted to make a call.  The
flashing was intiated by your Great Aunt Bertha turning a crank on her telefone (I
bet.)  The operator plugged her headest into Bertha's jack (bet that hurt) and
determined through verbal interaction what number Bertha wanted to call.  If the
reciving party's lamp was unlit, the operator rang the recieving party's fone and
connected Bertha's jack to the recieving party's.  If the recieving line was busy, the
operator told Bertha to fuck off and try back later.

   If the recieving party was served by another exchange, the operator called an
operator at the distant exchange through an interoffice trunk, and told her the number
of the recieving party.  If the recieving party's lamp was unlit the distant operator
rang the reciever's fone, and retuned to her donuts and coffee.

   More recently the request for service is made by simply lifting that handset off the
fone, closing a 48 volt DC circuit.  The flow of current is interpreted by the switch
at the central office as a request for service.  This current carries two concurrent
sine waves, one 350Hz and one 440Hz, which produce a cool sound in the earpiece, often
called the "dial tone."  The flow of DC contiues as long as the fone is off the hook,
and the switching facility uses this information,, specifically, in determining whether
the line is still in use.

   The number of the party to be called is conveyed to the switch by the caller with
either tones or pulses.  The early telefone was equipped with a spring loaded rotating
dial, which had numbered "finger-holes."  After tha caller spun the disk until blocked
by a stationary "finger stop," the disk would interrupt the DC flow as many times as
the nukber dialed (except for 10 times for the 0.)  If the number dialed was 4, as the
disk rewound, the DC circuit would be broken four times for about 6/100 of a seconf and
restored between each break for 4/100 of a second.  Each pulse cycle took about 1/10 of
a second (for those of you who can't add.)  Newer non-rotary fones, capable of pulse
dialing do this by interrupting the circuit with an electronic control.  Nimble
fingers can also do this by quickly hitting the hang-up button.

   More modern fones emit a pair of concurrent sine waves to communicate numbers to the
switch.  On a standard dial pad each button on the top row (1,2,3) emit 697Hz; second
row, 770Hz; third row 852Hz; and fourth row (*,0, and #) 941Hz.  The buttons in the
first column (1,4,7,*) emit 1209Hz; scond column, 1336Hz; thrid column (3,6,9,#)
1447Hz.  These tone pairs are interpreted by the switching facility as the number
pressed on the dial pad.  Although ancinet switches cannot interpret tones, new (all)
switches interpret pulses (for those old farts who refuse to get rid of the fone they
used in 1946.)

   The central office provides callers with an aural representation of the recieving
party's fone in the act of ringing with a simutaneous pair of tones called "ringback."
They are 440Hz and 480Hz, and bleep for two of each six seconds while the distant fone
is ringing.  (Ok, how many of you thought the sound was the actual fone on the other
end ringing?)

   The famous "line-busy" signal is comprised of simultaneous 480Hz and 620Hz tones,
bleeping one half of each second until the caller hangs up.  The "trunk-busy" or
"reorder" signal is issued when switching or transmission facilities are unable to
handle the call.  It is identical to the lin-busy signal but twice the rate.

   When all goes well, the recieving party's fone is sent a ringing signal, not audible
at the earpiece, but inciting a bell, chirping sounds, or even flashing lights.  The is
accomplished by a 20Hz signal fo about 74 volts, issued for two of each six seconds
until the ringing fone is picked up or the calling fone is hung up.

   A call to a party served by a central office other than one's own requires the use
of one of more interoffice trunks.  Older long distance lines used a 2600Hz signal when
the trunk was available.  When the switch began using the trunk, the caller's central
office ceased issuance of the tone.  The distant offce was alerted of the incoming call
by this change.

   More recently, (unfortunately) interoffice signalling has been moved from voice
lines to a seperate dedicated line.  A single data circuit can control thousands of
voice circuits, conveying telefone number, trunk availability, and other information.

   Line busy signals are no longer sent from the distant office.  A data signal is sent
via the signal circuit, initiating the generation of the audible signal at the caller's
office.  Previously, sending an audio signal from the distant office required the use
of a voice circuit, which is now left free for other users' conversation (but making
blue boxing impossible.)

   The caller's telefone number is also conveyed through the sperate circuit.  The
distant office knows the caller's number, and the recieving party may also get it
(ugh!)  It is sent to the recieving party's equipment as a shot burst of digital data,
encrypted by phase shift keying.  The reciever's equipment must decrypt the sigal, and
display it or otherwise act on it.  Depending on the number, the call may be
automatically rejected, prventing the fone from ringing, or it may be forwarded to
another location.

   Well, hopefully this short article has enlightened some of you lamerz out there.  If
you didn't understand part of it, the go kill yourself, because you don't deserve to
live.  If you already know this shit, the congratulations, you've just wasted credits
to downlad this.  Hopefully, I have enlightened at least one person and saved him from
the clutches of ignorance.  But then again, maybe not.

Copyright 1994 MONEY INCORPORATED
ALL RIGHTS MOLESTED BY MICHAEL JACKSON

MONEY INCORPORATED IS:  SLEEPY   SONIC FURY  THE BIG CH33S3  METHOD MAN