Quite some time ago I worked at a small company, and we had a PC in a remote location that we would occasionally connect to by directly dialing it up by modem. (this is in the pre-ubiquitous-Internet days). Well, of course, every now and then the computer would crash leaving us unable to perform its intended task, and also unable to answer our calls. After having to drive out there a few times just to hit the Reset button, I installed a circuit inside that "eavesdropped" on the phone line. If the phone rang more than X number of times within some period of time (meaning the computer had crash and was not answering), it reset the computer by way of a relay connect in parallel with the case button.