63 lines
2.1 KiB
Plaintext
63 lines
2.1 KiB
Plaintext
Unauthorised Access UK
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(0636) 708063
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10pm - 7am
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12oo/24oo
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The Charging Box (c) Stinky Pig Productions
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---------------- --------------------------
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What it does:
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The Charging Box is used to indicate when a call is being charged
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for and when it is not. Once installed, the box has two lights, a
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green and a red. Green means free and red shows that you are being
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stung by BT!
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Components:
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1 x green LED 1 x circuit board
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1 x red LED 2 x 10K ohm (1/4 watt) resistors
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2 x short lengths of wire 2 x small bulldog clips
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Circuit Diagram:
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| Line |
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| (50v) |
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|------ ------|
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|-----[]------O------|
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|-----[]------O------|
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Where [] is a resistor and O is an LED.
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NB. IMPORTANT! One LED should have it's anode towards the resistor
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and the other should have it's cathode towards the
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resistor.
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Connection:
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Build that onto the board and connect the two points marked line
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to the wire, with the bulldog clips at the end. The box should now
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be connected to the line in parallel with the phone.
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Operation:
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When the line is opened (Ie. the phone lifted) the green LED will
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light (if the read one does then just reverse the polarity of the
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box). Dialling numbers (by pulse) will cause the green LED to flicker
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but while you are making free calls it should never go out and the
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red LED will not light. As soon as the exchange starts charging for
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your call, the green LED will go out and the red LED glow.
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How it works:
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As the LEDs are in opposite directions, only one can light depending
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on the polarity of the current supply. This is exploited when
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the exchange begins charging as the polarity of the line is
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reversed.
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For more details contact me on The Outer Limits.
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Piggy The Pig
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Jan 88.
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