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TUCoPS :: Phreaking General Information :: swdial.txt

Switch Hook Dialing - an art nearly lost to the current generation (such that it is) of phreaks





Switch hook dialing
By: Captain B 

As you should know, before the event of DTMF (Dual Tone Multi Frequency)
or "touch tone" dialing, there was the standard old rotary dial. (Which,
is still accesible today on many touch tone phones through a switch marked
either T/P or tone/pulse). The principal on which rotary (or, pulse) dialing
works is by cutting the current on and off repeatedly. In other words, you
don't have to be using a rotary phone, or touch tone phone set to "pulse"
to be able to dial in this way. Another method to do it is called switchhook
dialing. I'll get into it in a bit. But first, some side notes. Although
rotary (pulse) dialing is definitely a slower way to dial than touch tone,
it does have a few advantages. For instance, if someone is tapped into your

line and recording you, or you're using an old cordless phone with no voice
scrambling technology, if you dial through rotary (pulse), the person recording
you won't simply be able to play back the click sounds made by rotary (pulse)
dialing to call back the same person you just talked to after hanging up.
(You can do that with numbers that are touch tone dialed). Also, there may
be DTMF decoders on the market, but I've yet to hear about any "Rotary decoders",
or anything of the like on the market. The only way I currently know of to
be able to tell what number was dialed is if you have a good ear, and listen
close to the number of clicks for each dialed digit. Or, perhaps you could
put a program together for handle that for you. Anyway, on to how to switchhook
dial: There's really nothing particularly complicated about 
it. It's just a matter of clicking the switchhook the same number of times
as each digit you wish to dial. The number zero is represented by 10 clicks
of the switchhook. And, in my area (Verizon country) clicking the switchhook
11 times represents the # key. (Although, this was only tested on Verizon
payphones. I've yet to try that on my home phone). Perhaps it should also
be mentioned that switchhook dialing won't work on COCOTS. That's because
the dial tone you hear Isn't the true dial tone in the first place on COCOTS.
However, if you physically bypass the COCOT, you can dial either rotary or
DTMF for the dicounted rate of zilch. Another, more complex way to simulate
rotary (pulse) dialing is to wire up a SPST momentary on/off switch between
the phone and the phone jack. But, why go to all that trouble when there's
simpler ways? From payphones, I will admit rotary (pulse) dial Isn't particularly
useful. Unless, say, the DTMF tones the keypad is putting out are too low
in volume, and therefore not being picked up properly on the line, thereby
keeping the dial tone on. Or, maybe a payphone that has a bad problem with
buttons staying stuck down when you push them. At any rate, just make sure
you use only Bell payphones when trying the switchhook dialing method. It's
the only ones I'm currently sure of that It'll work on. One final thing:
You must try to keep a steady rhythmn when repeatedly flashing the switchhook,
and don't do it too slowly. Do it at a fairly fast speed. Yes, it can take
a bit of getting used to at first. But, like with anything else, practice
makes perfect. One thing that'll help is the fact that you actually don't
have to push the switchhook completely down on each repeated flash. It only
need be down enough to cut the current off. You can determine just how far
the switchhook need be down by very slowly pushing down the switchhook until
the handset is muted. (Receiver speaker and transmitter mic muted). On payphones,
you can hold a finger or 2 under the switchhook cradle to prevent the switchhook
from going all the way down (That's my method). Or, develop a method that
you like, and works best for you. Rotary dial may be dead, but It's not forgotten.



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