The type I was referring to has two button on the key itself. One to unlock the doors, and another that causes the horn to beep as the doors lock. Also, one of the buttons will beep on and off to locate your car if you can't remember where your parked, or in case your being attack in a parking lot. Also called a panic button.
__________ Information from ESET Smart Security, version of virus signature database 4232 (20090710) __________ The message was checked by ESET Smart Security. http://www.eset.com
