128 lines
3.3 KiB
Plaintext
128 lines
3.3 KiB
Plaintext
|
|
X<>X<>X<>X<>X<>X<>X<>X<>X<>X<>X<>X<>X
|
|
|
|
-= PHONE GADGETS =-
|
|
|
|
Conference Caller
|
|
Hold Button
|
|
|
|
by
|
|
-- anonymous wizard --
|
|
|
|
X<>X<>X<>X<>X<>X<>X<>X<>X<>X<>X<>X<>X
|
|
|
|
>>> Standard Disclaimer <<<
|
|
Anything you connect to the phone lines
|
|
is *supposed* to be FCC registered, to
|
|
make sure it won't injure repairmen or
|
|
damage equipment. The gadgets des-
|
|
cribed in this file do NOT apply any
|
|
extra voltage to the line, and should
|
|
be safe. If in doubt, check with the
|
|
phone company before connecting any
|
|
stuff to your line. (These gadgets do
|
|
not put any extra "ringer equivalence"
|
|
on your line, either.)
|
|
|
|
X<>X<>X<>X<>X<>X<>X<>X<>X<>X<>X<>X<>X
|
|
|
|
CONFERENCE CALLER
|
|
|
|
If you have two phone lines, you can
|
|
this simple attachment to set up your
|
|
own conference calls. You'll never pay
|
|
to have an operator set them up for you
|
|
again. Once you've called the two
|
|
other people on your two lines, you
|
|
just throw the switch. All three of
|
|
you can now talk to each other.
|
|
|
|
Phone lines carry voices as audio
|
|
frequencies superimposed on DC control
|
|
voltages (around 40-50 volts when not
|
|
in use, with higher pulses when
|
|
ringing; around 10 volts when a phone
|
|
is being used -- I forget the exact
|
|
numbers, but those are close.)
|
|
|
|
The two lines can be connected through
|
|
capacitors, so the audio passes between
|
|
the two, but the DC voltages don't
|
|
interfere with each other. (If you
|
|
simply short the lines together, the
|
|
phone company may not like it!)
|
|
|
|
Use this simple circuit:
|
|
|
|
! !
|
|
|
|
red --------! !---o: o------ red
|
|
! ! :
|
|
(line 1) : (line 2)
|
|
! !
|
|
|
|
green--------! !---o o------green
|
|
! !
|
|
^ ^
|
|
capacitors DPST
|
|
.1 to 1 uf switch
|
|
(not critical)
|
|
(do *not* use polarized electrolytics!)
|
|
|
|
(This circuit is similar to the other
|
|
conference caller mentioned on the
|
|
Roman Forum, which doesn't have the
|
|
capacitors.)
|
|
|
|
X<>X<>X<>X<>X<>X<>X<>X<>X<>X<>X<>X<>X
|
|
|
|
HOLD BUTTON
|
|
|
|
This gadget also is a variation on one
|
|
posted on the Roman Forum.
|
|
|
|
Shorting the line is not a good idea.
|
|
A resistance of 1-2K is enough to hold
|
|
the line, without making the line look
|
|
screwed up to the phone company.
|
|
|
|
|
|
|
|
red ------o o----\\\\------ green
|
|
|
|
SPST 1-2K
|
|
switch
|
|
|
|
(It doesn't matter which direction you
|
|
connect this circuit in -- red-to-green
|
|
and green-to-red both work.)
|
|
|
|
If you like, you can add an LED that
|
|
will light whenever you have someone on
|
|
hold. Just connect the LED in series
|
|
with the switch and resistor (now about
|
|
500 ohms to 1.5k, depending on your LED
|
|
-- experiment!). Like this:
|
|
|
|
^^
|
|
!\ !
|
|
red -----o o----\\\\-----! >!--- green
|
|
! !
|
|
|
|
SPST sw. .5-1.5K LED
|
|
|
|
This circuit (with the LED) only works
|
|
if it's connected in the right direc-
|
|
tion. Phone wiring isn't always done
|
|
right; before you wire this one in
|
|
permanently, try switching the red and
|
|
green wires, and leave it in the
|
|
direction that works.
|
|
|
|
|
|
ENJOY!
|
|
|
|
|
|
X<>X<>X< anonymous wizard >X<>X<>X
|
|
|
|
|