🚀 go-pugleaf

Mike McCammant (mikemc@macshack.com) wrote:
: Actually 2600hz placed the phone ON-HOOK.  If is/was called SF or supervision
: frequency. If you had a call attempt up (mainly a toll call) and you sent
: a burst of SF, your local line would remain connected up, and the toll
: trunk would go on-hook then off hook.  You could then dial back out on the
: toll trunk using MF (similiar to DTMF of Touch-tone, but different)...

Thankfully someone got it right, but as there seems to be so much
misunderstanding of this, I figured I would clarifiy.... Blue Boxing...
On older electronic switches the 2600 tone was used to demark a trunk that
was on hook. Your phone is connected to a switch, which is connected to 
a bunch of trunks which are connected to other switches. When you place a 
long distance call, you pick up your phone and issue commands to your switch
(i.e. dial the number) at the prompt (i.e. the dial tone). The switch then
finds an open trunk which goes to the switch in the town you are calling,
and issues commands to the distant switch telling it to ring the other guy's
phone. If the phone is ringing, your switch send you the "ring" signal. (I am
simplifying a little, the switches are really hubed and there are differnet
layers of intra and inter LATA phone calls.) If the other guy picks up
you are connected through. On older switches, if there was no call on a
trunk, the switches would blast 2600hz (an annoyingly high pitched tone
chosen because it is easy to identify even on bad lines). Phone Phreaks
could (and still can, though it isn't easy anymore) call a long distance
800 number, and then once connected, blast 2600. The local switch would
ignore the 2600 as it wouldn't be listening to your side of the call until
you hung up. However, the remote switch would grab the 2600 and assume you
hung up the phone. Then you kill the 2600 tone, and the switch thinks your
switch is going to place another command. You now have control of the
switch. You can access internal operators and test numbers which cannot
normally be reached. You can tap phone calls, start conferences, make free
calls, or route your phone call through switch after switch all around the
world until you can't hear the other end anymore. It was a whole world to
explore. However, it cost the phone companies a fortune, and they evolved.
There are now a bunch of different tone systems it many different
countries, MF, ccitt, the french system, etc.... You CAN get in and play
around, but it isn't easy, it's risky, and it the only thing you
want out of it is free phone calls, there are much easiser ways. 
There are only a few people who still do this, and most of them live in
east-block time nations. Its done for the adventure and the technical
interest. In the US it is, for the most part, impossible (barring BFE
UTAH where you can still find SxSs!!!!). Now the switching is done    
out of band for the most part. The reason music sounds flat on the phone
is that the frequency range of a phone connection is very small. It is
limited to the normal speaking voice frequencies of humans... Most of the
cool sounds in your new acid-jazz album are probably way out of the freq
range. They cut off the freqs for conservation of resources. They can
stack a bunch of calls on one wire with frequency divison multiplexing
because the actual bandwidth of a phone line is far beyond that small
freq range you are allowed to use. They can also do out of band
signalling. What was 2600 is now 3380 or something, way out of the human
voice range. Also, you hear about high pitched screams or Captn'Crunch
whistles, you need alot more than just a 2600 tone to blue box with. You
need an MF generator. The MF matrix is different from the DTMF matrix,
although DTMFs often work inside the network, and MFs often work outside
the network. You also need the KeyPress MF which initiates commands, and
the STart MF which executes commands. Anyway, if you ever get a call from
Costa-Rica and after your friend from the international house hangs up,
there is a short, high pitched, bleep, you just heard a 2600 tone. The
remote switch was hanging up on you. Also, lemme just though something in
here. Hacking isn't about getting free phone calls or formatting hard
disks. Its about technology. Its about studying, experiementing, and
playing with fascinating new technology. If you found the above
interesting you should check out 2600. There is always something that will
get your mind buzzing with ideas. (This IS an engineering school, right?) :)
Tom  
-- 
=-=-=-=-=-=-= Tom Cross AKA The White Ninja / Decius 6i5 */^\* -=-=-=-=-=-=-=-
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