..

Doesn't X-10 all depend on radio transmissions.

X-10 sends its signals over the power wires. There is a "new" system (the
same folks that sell X-10 will also sell the new stuff) that uses RF.

I'm going to use that
to flash the porch light when the alarm goes off, but that's not
critical. If at all possible, I like to use hard-wired things.

Well, if the transmitter and receiver are on the same 120 volt circuit, it's
pretty reliable.


2b) A transformer/relay "package" that is approved and has isolated high
and low voltage sides. The "high voltage" wiring would come out in an
attached J-box. The "low voltage" stuff would be screw terminals. I
have
seen this but would not know where to get my hand on it.

Well, what it has now, the professional quality alarm (used by a
friend with an alarm business and over 1000 customers) comes with its
own big wall wart, 16.5 volts. The 110 has to be the same phase as
what supplies those light bulbs at other times, through their
respective switches, because if the light is already on when I arm the
alarm, I have to have the same phase 110 going to the lightbulb
through both sources. I'm sure even one reading already knows that.

I guess I could use a big, 250 or more watt isolation transformer. I
think it would be expensive to buy and it would have to run all the
time, just for those 2 minutes when I leave the house or return.
Whereas, what I had in mind wouldn't cost any additional money for
installation or running.