Hiya
My Brother-in-law has just bought a house where the previous owner had died, so no-one to ask questions of. Inside there is a small (about 3x2 inches) yellow plastic box mounted on the wall, with a small black plastic key (about 1.5 inches long) in it. To the left of the key hole, still part of the box, is what looks like it might be an indicator of some sort, but whatever position the key is turned to, the indicator stays the same.
It is positioned by the front door, and there is another one in the main bedroom.There are cables running to the boxes, but can't trace them without a lot of removing of fixtures/boards etc.
There is a burglar alarm fitted, but he doesn't have the code and so can't tell if it worked, or if it is related to this little key box.
Any ideas what they are.
Many thanks