http://www.the12volt.com/relays/page5.asp
http://files.thehoffmangroup.com/ins...letButtons.pdf
above are the links that you guys can use to check how this works.
I'm thinking if is reliable do to it because of the costs and time to do it, and because I found this one
http://www.digitalguarddog.com/mm5/m...ry_Code=a20000