First of all before you got out to buy
contacts there is two differnt kinds.
Normally open contact which means that the
contact are open and do not conduct any
signal across (ex. light switch) or the
normally closed cicuit which senses troube
when the contact come apart or contact wire
getting cut. <---most realiable and
secure. if the sensor is open you can
connect them in parallel , meaning the two
wires can be joined with other sensors, if
its a closed circuit they should be wired
as series like cheap christmas light, when
one light is missing they all go out. <---
example. so if one sensor trips the alarm
is sounded. I am sure the x10 system is a
closed circuit system, Call x10 to make
sure. You can get addition sensors at
www.smarthome.com www.homecontrols.com or
local radioshack is they still sell them.
I am writing this late at night, someone
please correct me if I am wrong in the
wiring. Also don't use to much wire to
extend the contacts. too much wire can act
as an antennae and product false alarms.
Good luck
