ron, one way is to use a dallas button, maybe maxim button now, roman may say to do it in a pic12. this could act like a "key" to your code. you could even time-out your code when you want to. cheers, ling -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads