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Switch Box
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    This tutorial is notable in that it is totally and
absolutely within legal bounds. It's only object is to
guide you in building a device with which you can control,
on many different levels, your home phone lines. It is
designed primarily for two phone numbers, although I
suspect that provisions for more than two can be easily
added. With it, you can put one or both phone lines on
hold with visible indicators of each lines status; conference
call with two people; change a phone from line #1 to line #2;
and lastly, make one phone line physically dead to outside
world. This is good, for instance, if you don't want to
recieve any calls, or if you want to stop someone from talk-
ing on that line really quickly.
    The circut is relatively simple to build and I believe
it is much more economical than buying something like Radio
Shack's line controller. It will require some knowledge of
electronics and the phone line in general, but I don't think
that should be a problem. I have personally found many uses
for the controller, and have put in into a pleasant "project
box" so it is not an eyesore.
    OK, now, let's start with the parts list --------

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                  *** Parts List ***

1. Two pushbutton (on-off) switches for hold
2. Two LED's for line status indication
3. One DPDT switch for conferencing
4. One SPST switch for line shut off
5. Another DPDT switch for phone line switching
6. Get some wire, you'll need it!
7. 2 modular phone plugs with at least 10 feet of wire each
8. Two 1.7K ohm resistors
9. *OPTIONAL* - Project Box
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                  *** Construction ***

    We will take the construction of the switchbox-controller
in parts. First, the hold switches and status indicators. The
following is a diagram of the essential circut:



               Pushbutton #1    LED
--------------------------!x!-----0---
Phone Line #1     1.7K Resistor      !
-----------------/!/!/!/!/------------

Some word of explanation is in order. First of all, the
second phone line hold is constructed the same as the first.
Basically, there are two wires come out of your phone line,
the red and the green. You have to experiment to find out
which one is connected to the pushbutton switch and which
one to the Resistor. To do this, just connect it in any
way and then turn the switch on. If the LED lights up, you
connected it right, otherwise reverse the connections.
Got it? Good, now do the same for line #2, following exactly
the same procedure.

    Now, let's do an easy one. This will be the line black-
out switch. First, decide which line you wish to black out.
Actually, you can do it to both lines if you wish, just get
an extra SPST switch. Now, connect the switch across the line
as follows:

--------------------------------!!!!!!!!
         x                      ! Hold !
        !x! <---Switch          !Circut!
         x                      !      !
--------------------------------!!!!!!!!

Don't worry that your line can't handle both circuts, it can.
To test out, pick up a phone on the line you have connected
the switch to and flip it on. There should be dead silence.
Now, turn it off. You should hear a dial tone. You have to be
an absolute idiot if this doesn't work.

    OK, let's see what we have so far. If everything is
working you should now have two hold circuts and a black-
out switch connected. Now it really gets tough!

    Next on the agenda is the conference switch. I have a
few precautions for you on this one. First, you have to know
what you're doing, and second, it doesn't work that well. The
reason it doesn't is because I am naturally very lazy and
didn't feel like adding the needed phone transformer. But,
it is still good for many uses, limited only by your imag-
ination (to use a cliche').
    First, take the double pole double throw switch into your
hand. It should look like this on the back:

                    ---------
                    - 1   2 -
                    - 3   4 -
                    - 5   6 -
                    ---------
          * Note - Numbers correspond to actual pins.
Now connect two wires to pins 3 & 4 and two wires to pins
1 & 2. The wires going to pins one and two are connected
across the first phone line and the wires from three and
four go across the second phone line. Test it out: Pick
up your phone (either line) and wait for dial tone. Then
throw on the conference switch. You should get a second
dial tone. Now dial 555-1212. You should now have two
D.A.'s on the line, asking each other "What City?". If not,
then reverse the connections to phone line #1 or #2, it
doesn't matter. Now it should work. If not, then recheck
EVERYTHING! You messed up!

Now for the last section - the phone line switcher. With
this, you can connect a phone directly to the switchbox and
have it operate from line #1 or line #2, depending on the
position of the last DPDT switch. Let me emphasize that this
is optional. Actually, all the circuts are - they are in-
dependent of each other and each can be built separatly or
together.
    Now, refering to the diagram of the DPDT switch above:
Connect two wires to pins 1 & 2. Then connect these to phone
line #1. Now connect two wires to 5 & 6 and connect these to
phone line # 2. Lastly, connect two wires to 3 & 4 and con-
nect the ends of these to a phone. That's it! Now, pick up
the phone and you should hear a dial tone. Throw the switch
and you should hear another dial tone. In some areas you may
dial '958' to hear exactly what number you are currently
connected to, but that should be a problem. If you really
can't figure it out, then either trace the circut back or
call one of the numbers and see if you get a busy signal or
if it rings.

Finally - Put the whole mess inside a project case, unless
you like the site of wires all over the place. This also
shouldn't be a problem if you know even the basics of
hardware construction.

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