Well, I made progress today....more like one step forward and two steps backward....I did some further tests with the living room detector during daylight while set on setting 2 and it seemed to behave properly when I walked across the room....got a trigger on each test.....Now for the two steps backward part.....Each day since the installation, I have been testing the alarm upon returning home from work by unlocking and opening the garage door without disarming....Each day prior to today, the test was successful with an alarm trigger. Today, I opened the door and.....nothing.....I went into the garage and opened the cellar door to the house and still.....nothing......The alarm appeared to be disarmed......When I arm up when leaving in the morning, I walk around to the back of the house near the room that the console is in and can hear the chimes and definitely heard the single chime that it was armed.....However, tonight when I got home, it appeared to be disarmed......I did some thinking and some footwork and came up with this scenario.....I have a gate at the end of my driveway that I keep locked. I have to get in and out of my vehicle to manually unlock a padlock upon departure and return.....the lock is unlocked until I drive through the gate and then the lock is put back in place. This requires me to remove my keys from the ignition as I keep all my keys together on one keyring, along with my car and house alarm keychain remotes.....To make a long story short, I pondered the possibility that perhaps in fumbling around with the keys, either my finger, or one of my keys may have bumped the disarm button....Whether it happened upon departure or returning home, I don't know....So I did a 'walk test'.....I closed the doors on the house and disarmed it before walking out to the end of my driveway. I was at that point about 80-90 feet from the house. I pointed my remote at the house and clicked 'arm'.......I then reached my garage and proceeded to open the door to see if it had in fact armed from that great a distance....The result: the alarm triggered.....so the range is greater than I had expected. I was able to arm up from 80 feet away, and on top of that, the console is located on the opposite side of the house (in the back of the house)from where I was standing at the end of the driveway.....So...I came away with two theories.....First, which is the one I am hoping for..is that I inadvertantly disarmed when I was fumbling around with the keys.....or Second...The system mysteriously disarmed itself....or was disarmed when a neighbor opened or closed a garage door opener or armed or disarmed their own security system which somehow is interfering with mine.......I will continue my daily garage door test routine, while being extra mindful of making inadvertent contact with the remote after arming up......and then will see what happens from there forward....