Martin, there are commercial devices for this but the accepted DIY
method is a 0.1uf/600V cap across the 120V legs. Note, this is for the
X10's carrier frequency. For more info, check the comp.home.automation
news group and X10's site at:

      http://www.x10.com

   - Tom

At 11:13 PM 1/13/98 GMT, you wrote:
>This is not exactly about a PIC, but I know that some of you out there
>have done some carrier current and/or X-10 stuff, so maybe you can
>help me.  I have some carrier current intercoms that work quite well
>as long as they are on the same half of the 240V circuit in my house
>(BTW, I live in Canada, 120V 60Hz, 240V feed to the house).  The
>problem is that many of the AC outlets I want to use are not on the
>same side of the wiring.  I know that a similar problem shows up with
>X-10, and I believe it is solved by placing a small value capacitor
>across the two halves of the 240V line, but I don't know exactly what
>type of cap, or what size to use.
>
>The intercoms use one of 3 carrier frequencies (FM modulation, 1KHz
>deviation) at 200KHz, 230KHz or 260KHz.  Can anyone suggest a suitable
>device to link the two halves of the circuit at carrier frequencies,
>tell me exactly where to put it (no cracks pleez), and alert me of
>anything I should look out for (I have done quite a bit of AC wiring
>in my 40 years - tomorrow - so I'm not a neophyte in that area).
>
>TIA - Martin.
>
>PS. maybe you should reply directly to me via email, this is quite
>off-topic
>
>Martin R. Green
>elimar@NOSPAMbigfoot.com
>
>To reply, remove the NOSPAM from the return address.
>Stamp out SPAM everywhere!!!
>
>