The Invisible Box
                                     By Lucky225
                               Email: Lucky225@verizonfears.com

Introduction:

   The invisible box will make it so that when you pick up a phone on
your phone line any of those in-use lights that tell if an extension
phone is picked up, wont light.

Theory:

  The theory is based off the same principles as the infamous blackbox
that used a 1.8k resistor to keep the phone line at 50v when you pick
up, which actually still works, but because of SS7 the voice path is cut
off from the party calling you, and the phone company doesn't allow a
voice connection any more until your phone goes off hook and there's
supervision.  The invisible box works by using high resistance to keep
the voltage at about 20 volts. This is accomplished by placing a
resistor of about 470ohms in series with your phone.  The phone is
approximately 215ohms and draws 28ma of current, which means when your
phone is off-hook there is approximately 6 volts on the phone line.
When you place the resistor in series with the phone line there is a
total resistance of 685ohms. Using ohm's law, 685 ohms times 28ma gets
you 19.2 Volts!  So the resistor keeps the phone line at about 20 volts,
and most in use lights only go off when there is about 15 volts or less
on the phone line.

Construction:

You will need a phone cord and a 470ohm resistor(Yellow, Purple, Brown).
You can get the resistor in a 5 pack at radioshack for $0.49. It
wouldn't hurt to have some wire stripers, and possibly electrical tape
or solder.  Strip the phone cord in the middle, dont cut the modular
jacks off.  You'll see 4 or 2 wires, usually black, red, green, and
yellow.  Dont worry about the black and yellow wires, in fact cut them
off they'll get in the way.  Leave the green wire alone, thats the
positive wire, and sense current flows from negative to positive and
we're trying to opose current so the voltage wont drop we leave it
alone! Finally, cut the red wire (that's the negative!) in half and
strip both ends, you're going to insert the resistor here.

Diagram:

(-) Red wire  470ohm
 -------------/\/\/\----------                           
 -----------------------------
(+) Green wire

Conclusion:

That's it, pretty simple huh?  You might be thinking that maybe there is
no real use for this because all it does it make it so that an in-use
light doesn't light when you pick up the phone.  But think of the
possibilities, you could go beigeboxing with this box and it might save
you if the person your beigeing off of has an in-use light and they
always look at it to see if their kid is on the phone, but because of
your trusty invisible box hooked up to the phone line that light never
comes on and they never pick up to yell at what they would think is
their kid.  Personally, I use it when I'm talking on my phone line but
want to use my main line to go on the internet, my mom is always
checking that damn in-use light and yelling at me, "You're on the
internet with my phone line! GET OFF NOW!" HA-HA! Now she'll never know!
The sad thing is I bet this even bypasses those lame $200 phone tap
detectors you always see on TV.

Okay time for greets:

Yari my beloved!, Spoonm!, Pooly, BigB9000, Xhype, Gizmo, Morbid Angel,
Lancomandr, phlux, cry0, syncron, Omega2, phreak2000.com! and anyone
else I left out!


-------
UPDATE
-------


After recently purchasing the 43-443 in-use light from radioshack, I
noticed that they detected current, not voltage, unlike the in-use light
on my mom's phone that only detects voltage drop.  However you can
defeat these by placing a 220ohm resistor in parallel with the phone
line and when your using your phone there won't be enough current to
light the light.  I have made an improved "invisible box" that defeats
both the voltage and current detector in-use lights. Below is the
diagram:

Red
Ring(-)   470ohm
---------/\/\/\------->
                     < 220ohm
                      >
-----------------------
Tip(+)
Green

If your in-use light still lights trying changing the resistor values as
the resistance of your phone may vary.