X10 "Noise"

["Simon Brazier" <simon@xxxxxxx>]

I've recently purchased a Visonic Powermax alarm system after reading
good reviews and comments on the Automated Home website.

When I setup the X10 interface by connecting the alarm panel to the
mains through the recommended XM10U, I'm noticing that I'm getting a few
spurious X10 commands and wonder if anyone can shed any light on this.

When the alarm is armed, A1 ON is sent, and likewise when the alarm is
disarmed A1 OFF is sent. This is correct and all works as expected. When
the alarm goes off, I'm supposed to get A2 ON and A2 OFF toggling in 1
second intervals. Instead I get B1 ON and B1 OFF toggling, and A2
toggling ON and OFF every 12 seconds. When I move the housecode from A
to F I get G1 toggling ON and OFF, and likewise whatever I set the
housecode to, I always get Housecode + 1 being sent. The funny thing is
that when I increase the unitcode, so that when the alarm is going off I
should be getting A7 for example toggling ON and OFF, I still get
Housecode+1 Unitcode 1. I'm picking up the X10 signals using the
Homeseer log if that makes any difference.

My question is this.... Is this likely to be X10 "noise" or a
fault with
the alarm ? Also, is there any housecode that is less susceptible to
noise than others, or could it be the XM10U isn't transmitting a strong
enough X10 signal so there is some false reception ?

Any thoughts ?