I have an X-10 system (door, window sensors, motion detectors etc) for many years and an SC1200 consol. I armed the system before I left my home for the winter. Yesterday, my grandson went to check on my home. He tried to disarm the system from outside the door with a keychain remote that I had properly linked and checked a couple of weeks ago before I left. It did not work, so when he opened the door, the alarm sounded. He then tried to disarm standing next to the consol, with the remote, using the consol itself and using an old IBM remote (all of which worked previously) all to no avail. I was on my cell phone with him and had him pull the plug on the consol and remove its batteries to stop the alarm. Coincidentally, my landline phone, connected to the consol and programmed to call my cell on an intrusion was out of service due to Verizon changing from copper to fiber. Are these two things connected and what do you think caused him to be unable to disarm the system?
