You’ve got an aftermarket car alarm system in the used car you just bought and you need to know what brand it is. There are a few ways to determine this. The easiest is to look at the remote. The maker’s name will be engraved or stamped into the plastic of the remote. If this is somehow worn away or missing, look under the hood at the siren attached to the system. The maker’s name will be emblazoned on it very conspicuously. Makers of aftermarket car alarm systems want people to know who is protecting your car. The last way is to locate the control module and read the name on the sticker on the cover.
For more info, see Top 5 Highest Selling Car Alarm Systems