I never thought I'd be posting to this thread by my non-existant TCH car alarm went off about an hour ago. Beeping horn and flashing lights.

We were sitting in the car. I had just shutdown the system, but instead of getting out I cycled the power button to "on" to get a last look at the instrument display. While I was cycling the DISP button the alarm went off! I had no idea what happened nor what to do. I cycled the power switch and it finally stopped.

I don't know what this is, since no alarm system was on the invoice. I've got no experience with car alarms -- my last two cars had just the passive engine shut-off variety. It has me spooked because I don't know what I did or how to avoid it in the future.