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- Magazine
- This phile dated 03/14/1994
-
- Volume 2, Issue 3
-
- You can always find BTR on PsychoTron BBS
- └────────────────────────────────────────────────────────────────────────────┘
-
- This Beneath The Remains Issue Is On making a red box. Although I edit
- this file, I think that some recongition goes to the original author.
- The only reason this is in here, is because it is like the first file on
- making a red box that actually works. Hats Off To JD "Bob" Dobbs!
-
- BUILDING A RED BOX
- by JR "Bob" Dobbs
-
-
- Essentially,the red box is a device used to fool the phone company
- into thinking you are depositing coins 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
- -------------
-
- Operation is simple. 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
- nickel before "simulating" more coins or place your call through the
- operator with 0 + 7d. 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 50k 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.
-
-
- CONSTRUCTION
- ------------
-
- Assemble the circuit as you wish. Component placement is not
- critical. I found the easiest method was to use point-to-point wiring
- on a "universal" PC grid board with solder ringed holes. Use sockets if
- you aren't a whiz with a soldering iron. Be sure to leave easy access
- to the potentiometers for alignment.
-
- ALIGNMENT AND TESTING
- ---------------------
-
- For alignment, a frequency counter and tiggered sweep oscilloscope
- are extremely handy (but not absolutely necessary.)
-
- 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, adjust the 20k pot between pins 1 and 6 for an output
- of 1700hz. Now adjust the 20k 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. (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, 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 50k 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.)
-
- The remaining adjustments are made by ear.
-
- Leave the selector switch in the "N" position. 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's no such thing
- as spare change.!
-
- Parts list for Red Box
- ----------------------
-
-
- Semiconductors
- --------------
-
- (2)556 dual timer
- (1)741 Op Amp
- (1)1N914 Switching Diode
-
-
-
- Resistors
- ---------
-
- (6)10k (1)4.7k
- (2)100k
- (4)50k PC Mount Potentiometer
- (2)20k Multi-Turn Potentiometer
-
-
-
- Capacitors
- ----------
-
- (10)0.01uF (1)1.0uF
- (2)10.0uF Electrolytic
-
-
-
- Miscellaneous
- -------------
-
- (2)14 Pin Dip Socket
- (1)8 Pin Dip Socket
- (1)3-position Rotary Switch
- (1)Momentary Push-Button Switch(normally open)
- (1)SPST Toggle Switch
- (1)Speaker or Telephone Earpiece Circuit Board
- (1) Box
- (1) 9v Battery Clip
- Mounting Hardware
-
-
- SCHEMATIC DRAWING
- -----------------
- /
- ┌──S1┘ ──┬─────────┬────────┬────────┬────────────────┬─────────────┐
- +9v R1 R2 │ │ │ │
- ├───C1────┤ │ R3 │ │
- │ │ ┌───┤ ├────┬─C2─@q S3 @n │
- o ┌───┴────┴───┴───┐ │ R5 │ @d │ │
- o─┤ │ 6 4 14 │ R4 │ │ │ ├──┐ │
- S2 o ┌─┤5 13├────┤ g │ ├───┐ │ │ │
- │ │ │ │ │ │ │ │ R9<─┘ │
- g └─┤10 (IC1556) 8├─┐ R6<─┐ │ R8<──┘ │ │
- │ │ │ │ │ │ │ │ │
- ┌────┤9 12├─┴──┼──┘ ├──┐ │ │ │
- │ │ 3 11 7 2 1 │ C3 │ │ │ │ │
- │ └─┬──┬───┬──┬──┬─┘ │ R7<─┘ │ │ │
- │ │ │ │ └──┤ g │ │ │ │
- │ C4 C5 │ ├────────────────┴──────┴───────┘ │
- │ │ │ │ C6 │
- │ │ │ │ │ │
- │ g g g g │
- │ │
- └──┬─────┬───────┐ │
- R11 │ R12 ┌───┐ │
- ┌──┐ │ │ │ │ v │
- v │ │ ┌──┼──┐ ├────┴──R13──┐ │
- ┌───R10─┴──┤ │ │ │ │ │ │
- │ ┌─┴──┴──┴──┴────┴────┐ │ │
- │ │ 1 4 14 10 13 │ │ │
- │ │ 8├──┬────┤ │
- ├──────┬─┤6 │ │ C12 │
- │ │ │ 12├──┘ │ │
- │ └─┤2 IC2 556 │ │ │
- C7 │ │ g │
- │ ┌──┤3 11├─────┐ │
- │ │ │ 7 5 9 │ │ │
- g C8 └────┬───┬───┬───────┘ C11 │
- │ │ C9 C10 │ │
- │ │ │ │ g │
- g │ └─┬─┘ │
- g │ │
- │ ┌─────────────────┬──────────────┘
- │ │ │
- │ R14 │
- │ │ │\ │
- │ │ │ \ │
- ├────────────┼───────────│3 \│
- │ │ │ 7 \
- C13 R15 │IC3 \
- │ │ │741 6/──────┐
- │ │ │ 4 / │
- │ │ │ / │
- g g ┌──┤2 / │ │
- │ │/ │ │
- │ g │
- └──────────────────┤
- C14
- │
- Speaker
- │
- g
-
-
-
- Schematic part variables list.
- ------------------------------
-
- Resistors
- ---------
- R1 - 10k R2 - 10k R3 -4.7k R4 - 10k R5 - 10k R6 - 50k
- R7 - 50k R8 - 50k R9 - 50k R10- 20k R11- 10k R12- 10k
- R13- 20k R14-100k R15-100k
-
-
- Capacitors
- ----------
- C1 - 0.01uf C2 - 1N914 switching Diode C3 - 1.0uf C4 - 0.01uf
- C5 - 0.01uf C6 - 10uf C7 - 0.01uf C8 - 0.01uf C9 - 0.01uf
- C10 - 0.01uf C11 - 0.01uf C12 - 0.01uf C13 - 0.01uf C14 - 10uf
-
- Switches
- --------
- S1 - SPST toggle
- S2 - Momentary push button N.O. labeled "Deposit"
- S3 - 3-position rotary switch
-
-
- Miscellaneous
- -------------
- g - Ground
- @q - Label "quarter"
- @d - Label "dime"
- @n - Label "nickle"
-
- If any of you ppl know about digital then here is the formula:
-
-
- Charge Time(Output High) - 0.693(R1 + R2)C
- Dicharge Time(Output Low) - 0.693(R2)C
- Period 0.693(R1 + 2 * R2)C
- Frequency 1.44 / ((R1 + 2 * R2)C)
-
- Duty Cycle - Time High = R1 + R2
- Time Low = R2
-
- -+\+-
- A BTR production
- All rights lost.
-
- -rk
-