==Phrack Inc.==
Volume Three, Issue Thirty-Three, File 9 of 13
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|| A Real Functioning RED BOX Schematic ||
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|| Written by: R.J. "BoB" Dobbs ||
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::What is a Red Box?::
Essentially, the Red Box is a device used to fool the phone company's
computer into thinking coins are deposited into a payphone. Every time you
drop a coin into a payphone, the phone signals the type of coin inserted with
one or more bursts of a combination of 1700hz and 2200hz. The tone bursts are
coded as follows:
Nickel : One 60 millisecond pulse
Dime : Two 60 millisecond pulses separated by 60 milliseconds
Quarter: Five 35 millisecond pulses separated by 35 milliseconds
::How to use it::
Simply dial a long distance number (some areas require you to stick in
a genuine nickel first), wait for the ACTS computer to demand your cash, and
press the "deposit" button on the red box for each coin you want to simulate.
The coin signals are coupled from the red box into the phone with a small
speaker held to the mouthpiece. For local calls, either you must first deposit
a genuine nickle before simulating more coins or place your call through the
operator with 0+xxx+yyyy. Use some care when the operator is on the line -
sometimes they catch on to your beeper ploy.
::Circuit Operation::
Each time the pushbutton is pressed, it triggers half of IC1, configured
as a monostable multivibrator to energize the rest of the circuit for a length
of time determined by the setting of the coin selector switch. This in turn
starts the other half of IC1, configured as an astable multivibrator, pulsing
on and off at regular intervals at a rate determined by the 100k pot between
pins 12 and 13. The output of the astable thus alternately powers of IC2,
configured as a square wave oscillator, providing the required 1700hz and
2200hz to the op amp which acts as a buffer to drive the speaker.
::Alignment & Testing::
When you are making this thing by no means should you use a 9v AC to DC
adapter! I also suggest not using a bread board. So be careful with that
sodering iron. Both of these things will cause you problems.
For alignment, a frequency counter is desired but you can use a good
oscilloscope as well. (These are not ABSOLUTELY necessary, but to help.) In
order to figure frequency in Hz with your scope you can use the following
formula.
1 S = The measurement of the wave that is on the display
Hz = -----------
S*(T*10^-6) T = The setting of the time selector (milliseconds)
1
Hz = ------------------ Hz = 2198
9.1 * 50ms * 10^-6
Carefully remove IC1 from it's socket. Install a temporary jumper from
+9v supply to pin 14 of IC2 and temporarily disconnect the 0.01uF capacitors
from pins 5 and 9 of IC2. Power up the circuit. Measuring the output from pin
5 of IC2 with the frequency counter or scope, adjust the 50k pot between pins 1
and 6 for an output of 1700hz. Now adjust the 50k pot between pins 8 and 13
for an output of 2200hz from pin 9 of IC2. Remove the temporary jumper and
re-attach the capacitors to pins 5 and 9 of IC2, and re-insert IC1. (Note: if
no frequency counter is available, the outputs can be adjusted by ear one at a
time by zero-beating the output tone with a computer generated tone of known
precision.)
Next, using a multimeter, adjust the 10K pot at the cathode of the
"quarter" diode for resistance of approximately 8K ohms. (This sets the
difference between the duration of the quarter pulses and those of the
nickel/dime -- fine tuning of this ratio may be necessary durring the latter
stages of alignment; this can be done by ear.)
Now, temporarily disconnect the wire between pins 5 and 10 of IC1. Set
coin selector switch in the "N" (nickel) position. With the oscilloscope
measuring the output from pin 9 of IC1, adjust the 100k pot between pins 12 and
13 of IC1 for output pulses of 60 millisecond duration. Reconnect the wire
between pins 5 and 10. (Note: If no scope is available, adjust the pulse rate
by ear using computer generated tones for comparison.)
Leave the selector switch in the "N" position. Adjust the 50K pot
labeled "Nickel" for a single beep each time the deposit pushbutton is pressed.
Next set the coin selector switch to "Dime". Adjust the 50k pot labelled
"Dime" for a quick double beep each time the pushbutton is pressed.
Finally, set the selector to "Quarter". Adjust the 50k pot labelled
"Quarter" until exactly 5 very quick beeps are heard for each button
press. Don't worry if the quarter beeps sound shorter and faster than
the nickel and dime ones. They should be.
::Conclusion::
If all went well to this point, your red box should be completely
aligned and functional. A final test should now be conducted from a payphone
using the DATL (Dial Access Test Line) coin test. Dial 09591230 and follow the
computer instructions using the red box at the proper prompts. The computer
should correctly identify all coins "simulated" and flag any anomalies. With a
little discretion, your red box should bring you many years of use. Remember,
there is no such thing as spare change!
::Parts list for Red Box::
2 556 Dual Timer IC's 8 0.01uF Caps
1 741 Op Amp IC 2 0.1uF Cap
2 1N914 Diodes 1 1.0uF Electrolytic Cap
5 10k Resistors 2 10uF Electrolytic Caps
1 4.7k Resistor 1 3 Position Rotary Switch
2 100k Resistors 1 SPST Toggle Switch
1 100k PC Mount Pots 1 Momentary Push Button Switch (n/o)
3 50k PC Mount Pot 1 9v Battery Clip
1 10k PC Mount Pot 2 14 Pin Dip Socket
2 50k Multi-Turn Pots 1 8 Pin Dip Socket
::Schematic::
_
+9__S1/ _____________________________________________________________
| | | | | S3 |
R1 R2 | R3 o @ o |
|___C1___| _____| |_________|/___ / o \___ |
| ____|_____|_____|____ | | |\ | | _| |
_| o | 6 4 14 | R4 R5 D1 | | R9< |
S2 | o _|5 13|_____| | | |__ | |
| | | | |__ g | _| | |
g |_|10 IC1 8|_ _| | R8< | |
| 556 | |__R6< |__ | | |
_|9 12|_| _| | | |
| | | |__C2__g R7< | | |
| |_11___3___7___2___1__| | | | |
| | | | |___|_______________________|____|____| |
| | C3 | | |
|__|/| | | C4 |
| |\ | | | |
| D2 g g g |
|_____________________ |
| | | |
___ R10 | R11 ___ |
v | | | | | v |
__R12 |__| ___|___ |__| R13__ |
| _|___|___|___|____|_ | |
| | 1 4 14 10 13 | | |
| | | | |
|_______|6 8|_______| |
| | | IC2 | | | |
C5 |__|2 556 12|__| C6 |
| | | | |
g __|3 11|__ g |
| |_____7___5___9______| | |
C7 | | | C8 |
| | C9 C10 | |
| | |___| | |
g g | g |
| |
| ________________________________|
| | |
| R14 |
| | |\ |
| | | \ |
|___________|___________|3 \|
| | | 7 \
C11 R15 |IC3 \
| | |741 6/___
g g | 4 / |
| /| |
g_[speaker]___C12______|2 / | |
| |/ g |
|_______________|
::Schematic Parts Code::
R1:10K R4:10K R7:50K pot R10:10K R13:50K pot
R2:10K R5:10K R8:50K pot R11:10K R14:100K
R3:4.7K R6:100K pot R9:50K pot R12:50K pot R15:100K
C1:0.01uf C4:10uf C7:0.01uf C10:0.01uf
C2:1.00uf C5:0.01uf C8:0.01uf C11:0.10uf D1 :1N914
C3:0.01uf C6:0.01uf C9:0.01uf C12:10uf D2 :1N914
S1 - SPST toggle
S2 - Momentary push button Normally Open
S3 - 3-position rotary switch g - Ground
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