tim kettring wrote:
Or you can just buy the right smokes from alarm shops , be sure to
order 1 " terminator " unit ( i think it is called for each ) ( they
alert the alarm box that a wire has been cut ) , that is on most
professional alarm boxes ( like the Z-900 etc..by aritech corp )
...thats 12v 0v AND 6v sensing too , probably not on most
non-professional alarm boxes .

Tim , CET , previous alarm installer for 1 year .

Right- and there are models that run off 120VAC with battery backup, and
they are alarmed as well as alarm- meaning central alarm control can
cause smoke alarm to sound via NO or NC inputs- as well as other way
around. Generally you want latched operation requiring manual reset-
making that transistor thing inadequate.