Thanks again.=A0 Sai On Friday, January 3, 2014 11:21 PM, IVP wrote: =20 > I am assuming the telephone line was being used to send a PWM signal? At first it was just a 5V signal to the doorbell controller. After some false alerts I tried a coded signal, but that occassionally went off on its own too. There was just too much wire ready to pick up noise. The only sensible thing was to switch to RF, and in part because it was easier to move the whole lot if she ever changed buildings, which she did about 3 years ago. > The reason behind choosing a garage door sensor was that the > sensor has to be off-the-shelf. I didn't buy anything particularly special and I'm sure the sensor you have is fine. Joe --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .