Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!newstop!exodus!oobleck.Eng.Sun.COM!bender
From: bender@oobleck.Eng.Sun.COM (Michael Bender)
Newsgroups: sci.electronics
Subject: Re: X-10 switches used in 4-way circuit
Keywords: X-10
Message-ID: <7523@exodus.Eng.Sun.COM>
Date: 7 Feb 91 01:16:27 GMT
References: <463@sunpix.East.Sun.COM>
Sender: news@exodus.Eng.Sun.COM
Organization: Sun Microsystems, Mt. View, Ca.
Lines: 56

In article <463@sunpix.East.Sun.COM> cram@sunpix.east.sun.com (Marc W. Howard) writes:
->	Is there a way to use the X-10 three way switch in a 4-way (i.e.,
->three or more switch controlled) circuit?  I have one such circuit in my
->house that I'd like to control.  I notice that you can buy the non-active
->half of the three way switch pair as a separate item; does this imply
->that there is a way to use two of them and the three-way master switch in
->a four way circuit?

I don't know if I can answer your question, but I'll tell you what I
found out about the 3-way X-10 wall switches.  First, some background
on the devices for readers not familiar with what we're talking about:

  The X-10 system has as one if it's remote modules a drop-in replacement
  for a 3-way wall switch.  One of the units is a standard X-10 wall switch
  module with an extra wire coming out, and the other is a passive device
  considerably small, with 3 wires coming out if it.

  The reason that I wanted to find out about how the passive switch worked
  was that it was only rated for 1/10 amp, which works out to about 12 watts
  at 120VAC. This seemed strange to me, as the active switch module is rated
  to handle 500 or 600 watts.  Well, when I was installing several of these
  switches this weekend, I wondered how exactly the passive switch worked,
  and this is what I found out.  The passive switch has 3 wires - 2 blue and
  one red.  The two blue wires are connected internally to each other, and
  also to a contact in the switch.  This contact is connected, via either a
  large value resistor (I think) or a capacitor, to the red wire, so that
  pressing the button on the passive switch completes the connection between
  the red wire, through the resisitor, to the other two blue wires.  Here's
  how I think it's wired:

		active switch module
                     +---------+		   passive switch module
         +------+    |         |                   +--------------------+
         |      |    |         |        ||   blue  |                    |blue
    <----+ lamp +-------triac-----------||----------------+------------------>
     line|      |    |    |    |        ||    red  |      +--/\/\/\--+  |line
         +------+    |    +-------------||-----------+      resistor |  |
                     +---------+        ||         | |           switch |
                                                   | |               |  |
                                                   | +---------------+  |
                                                   |                    |
                                                   +--------------------+

OK, with that theorey out of the way, I think if you just get another
passive switch and wire it's blue wires in series with the blue wires
from the first passive switch, or anywhere in the path of the current
carrying wires, and provide a path from the 2nd passive switch's red
wire to either the red wire of the first passive switch or the control
wire of the active module (forgot which color it is ff hand), you should
be able to make an n-way remote controlled switch.

mike
--
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