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| How to build a BLACK BOX |
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| (Also known as a mute box) |
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To all who dare --
What is a BLACK BOX? A BLACK BOX is a device that is hooked up to your
fone that fixes your fone so that when you get a call, the caller doesn't get
charged for the call. This is good for calls up to 1/2 hour, after 1/2 hour
the Fone Co. gets suspicious, and then you can guess what happens.
The way it works:
What this little beauty does is keep the line voltage from dropping to 10v
when you answer your fone. The line is instead kept at 36v and it will make
the fone think that it is still ringing while your talking. The reason for
the 1/2 hour time limit is that the Fone CO. thinks that something is wrong
after 1/2 an hour of ringing.
All parts are available at Radio Shack. Using the least possible parts
and arrangement, the cost is $.98. And that is parts for two of them! Talk
about a deal! If you want to splurge then you can get a small PC board, and
a switch. There are two schematics for this box, one is for most normal
fones. The second one is for fones that don't work with the first. It was
made for use with a Bell Trimline touch tone fone.
** Schematic 1 for most fones **
** LED ON = BOX ON **
FROM >--------------------GREEN-> TO
LINE >--! 1.8k LED !---RED--> FONE
!--/\/\/\--!>--!
! !
------>/<-------
SPST
Parts: 1 1.8k 1/2 watt resistor
1 1.5v LED
1 SPST switch
You may just have two wires which you connect together for the switch.
** Schematic 2 for all fones **
** LED ON = BOX OFF **
FROM >---------------GREEN-> TO
LINE >------- ---RED--> FONE
! LED !
-->/<--!>--
! !
---/\/\/---
1.8k
Parts: 1 1.8k 1/2 watt resistor
1 1.5v LED
1 DPST switch
Here is the PC board layout that I recommend using. It is neat and is very
easy to hook up.
Schematic #1 Schematic #2
************** ****************
* * * ------- *
* --<LED>--- * * ! ! *
* ! ! * * ! <SWITCH> *
* RESISTOR ! * * ! ! ! *
* ! ! * * ! ! / *
* -------- ! * * ! ! \ *
* ! ! * * ! <LED>! / *
* --SWITCH-- * * ! ! \ *
* ! ! * * ! ! / *
* ! ! * * ! ! ! *
* ! ! * * ! !-! *
***!******!*** ***!********!***
*** These last few lines were inserted by hypothesis! --- The Director ***
Once you have hooked up all the parts, you must figure out what set of
wires go to the line and which go to the fone. This is because of the fact
that LED's must be put in, in a certain direction. Depending on which way
you put the LED is what controls what wires are for the line & fone.
How to find out:
Hook up the box in one direction using one set of wires for line and the
other for fone.
*NOTE* For Model I switch should be OFF.
*NOTE* For Model ][ switch should be set to side connecting the LED.
Once you have hooked it up, then pick up the fone and see if the LED is
on. If it is, the LED will be lit. If is doesn't light then switch the wires
and try again. Once you know which are which then label them.
*NOTE* - If neither directions worked then your switch was in the wrong
position. Now label the switch in its current position as BOX ON.
How to use it:
The purpose of this box is not to people who call you so it would make
since that it can only be used to receive calls. When the box is *ON* then
you may only receive calls. Your fone will ring like normal and the LED on
the box will flash. If you answer the fone now, then the LED will light and
the caller will not be charged. Hang up the fone after you are done talking
like normal. You will not be able to get a dial-tone or call when the box is
on, so turn the box *OFF* for normal calls. I don't recommend that you
leave it on all the time, as you don't want it to answer when Ma Bell calls!
