151 lines
8.1 KiB
Plaintext
151 lines
8.1 KiB
Plaintext
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Ideas in Red Boxing: Mercury Switches and Brute Force:
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By: Cybernetik
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January 1992
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Introduction
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---------------
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Radio Shack's DTMF Dialer (cat # 43-141) can be easily modified
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to produce the same frequencies that Pay Phones use for
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quarter/nickel/dime signaling back to Ma Bell. This is done by
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switching the crystal in the unit from 3.579Mhz To 6.5535 MHz. This
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information is completely covered in another file (See 2600
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Magazine for details) and will not be covered here.
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What I will attempt to cover in this article is 1) A simple way of
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modifiying the dialer to switch between DTMF and Red Box Tones,
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and 2) A low-cost idea for building the red box from scratch.
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Parts Needed
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Ohm Meter
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Solder
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Soldering Iron
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Epoxy or Duco Cement
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XT1 6.5535 Mhz Crystal <You should know this by now!>
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M1,M2 2 Sub-Micro-Mini Mercury switches
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Don't get the ones that radio shack sells. They're WAY
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too big. They'll never fit inside the case.
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Our goal here is to fit _everything_ inside the case. This box
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will function exactly like Count Zero's "Combo Box" <I perfer to
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call it a Pink Box, seeing as it combines both the features of
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White and Red boxing>
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Schematic C R Y S T A L S
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---------------- 3.5xx Mhz 6.5535 Mhz
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-=-=-=-=- -=-=-=-=-
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M1 \ | M2 \ |
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O-----------------------------------+-------|-------------+-------+
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pads on circuit board | |
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where original crystal was removed from | |
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O-------------------------------------------+---------------------+
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Step-By-Step Construction Details
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------------------------------------
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** REMOVE ALL BATTERIES BEFORE CONTINUING! **
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1> Disassemble the dialer. Remove the 4 screws holding the case
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together, and save them. Some prying is necessary to split the
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case open, and should be done with the utmost caution. You
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_MAY_ desolder the two yellow wires holding the speaker to the
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circuit board if you want more room to work in, so long as you
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remember where you removed them from. Placement of these two
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wires is not crucial. You don't have to remember which wire goes
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to what pad, just where you removed them from. (Which will
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probably be near the top of the unit)
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2> Carefully remove the original crystal from the circuit board.
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This will be a small silver cylindrical object, roughly 4 cm long and
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.25 cm wide, Soldered horizontally above the battery case, on the
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circuit board. Save it!
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3> Using an OhmMeter, find out the orientation of the two mecury
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switches. Hold the leads to each side of the switch, turning
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the switch upside down and right side up until you get a
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reading of ZERO on the ohmmeter. This means that you've got a
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connection through the switch. Mark an arrow or something on
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the switch so that you can remember the orientation.
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4) Using Expoy or Duco Cement, Attach the mercury switches, to the
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circuit board , so that one's orientation is UP, and the other,
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DOWN. When I speak of UP And DOWN, I'm talking about UP and DOWN
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in relation to the entire unit. UP means pointing towards the
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top, where the three buttons are. Down means pointing towards the
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battery case.
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This is exteremly important. If you make a mistake, and
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have them both in the same direction , the switching action of
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the mercury switches will be meaningless.
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5) Solder one wire to each leg of the switches. Solder the
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other end of these two wires to the bottom pad that you removed
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the original crystal from.
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6) Solder a wire from the top pad to a leg on the 3.5535MHz Crystal.
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7) Solder a wire from the top pad to a leg on the 6.5535MHz Crystal.
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8) Solder the remaining leg on the 3.5535 MHz Crystal to the
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remaining leg on one of the mercury switches.
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9) Solder the remaining leg on the 6.5535 MHz Crystal to the
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remaining leg on the other mercury switch.
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** ALWAYS REFER TO THE ABOVE SCHEMATIC IF YOU GET CONFUSED! **
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TAKE CARE WHEN SOLDERING! THE CIRCUIT BOARD IS WIMPY,
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AND COPPER PADS WILL JUST MELT OFF THE BOARD IF GIVEN EXTREME
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HEAT!
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Reassembly
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-----------
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10) If necessary, remove the Piezo Speaker (the smaller one) to
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make room for the new parts. This speaker is only used during
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the programming of the dialer, and you can probably live
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without it. Clever people can move this to a different location
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within the dialer.
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11) Cement the two crystals inside the dialer. Make sure of a few
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things: The bodies of the crystals are metal. If you want to
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place them in an area with lots of surrounding chips and parts,
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place cement down first, then the crystal to prevent shorting.
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The expoy can act as a wonderful insulator, and give you much
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more freedom as far as parts placement goes.
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12) Place the back on the dialer, push it together, and insert the 4
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screws again. Tighten.
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Testing/Troubleshooting
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---------------------------
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Turn the dialer on. Insert batteries. Toggle the STORE/DIAL switch
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to STORE. Store 1 * in P1, 2 *'s in P2, and 5 *'s to P3.
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Return the switch to DIAL.
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Press P3. If you hear quarter tones, then you're halfway there.
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Turn the unit upside down. Press P3 again. If you're hearing DTMF
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tones, You're set.
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Depending on how you wired the mercury switches, You may have to
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flip the unit around to hear the different tones. I've got the
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Red Box tones active when I turn my unit upside down, which I
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think is perferred. (It tends to be a bit more discret)...
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************
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Part Two
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************
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So, now that you've got a decently looking/functioning Pink Box,
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go off and try it. Bone AT&T a few times.
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If you're intrested in building a Red Box from scratch, I'll offer
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a simple block diagram, and some ideas. I'm not in the mood to
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type out a complete schematic for it, but If I recieve enough
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requests, then I'll provide complete details.
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Insane techincal discussion follows. Ask me questions if you can't
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understand me. Don't sit there being confused.
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****
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A red box can be created with 4-5 chips. You'd need 2 XR2207 VCO's
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(Voltage Controlled Oscillator), an LM386 Audio Amplifier, a 556
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Timer to do your timings for you, and a 74191 counter chip.
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In theory: The duty cycle of the 556 would control the Make/Break
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ratio of the tones, acting as a clock. You'd have to adjust this
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ratio with either a scope or freq counter, taking a bit of time,
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but it'd be worth it. A scope would be preferable, because you
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could SEE the timings and adjust accordingly.
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The 74191 would be given the output of the 556. Some arrangement of
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gates would tell the 74191 when to stop, and you'd switch these
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gates, on and off with three switches. It may even be easier to
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have three switches controlling the 74191's SET inputs in binary.
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(You'd have to hold swithes 3 and 1 to get 5 quarter 'clicks'. Not
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too elegant, but functional.)
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You'd have to set the two VCO's to the approiate frequency using
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potentionmeters. Simple if you've got a freq counter. Also, you'd
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have to set the VCO's to function with a sine wave.
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This is only a thought. I wouldn't want to go through the trouble of
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building this, seeing for $30 you can toss one together via radio
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shack...
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---------------------------------------------------------------------
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Any questiPOk, I was Wrong about fittin that shit in te dialer..
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V<EFBFBD><EFBFBD>R<EFBFBD><EFBFBD>T.617
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