hairdye

Right heres another one if anyone knows an answer please.
When i bought my car it didnt have an alarm or so i thought. Anyway i had one fitted by the garage i bought the car from, but on my spare key fob it looks like there was already an alarm fitted. Im not sure if it would be standard subaru or not but the key fob is one where the key folds in.There is also an led in the car what looks like could be for the other alarm.When i press the key fob the light on the key fob lights up but it doesnt do anything.How would i find out how to make the other alarm work if needed and is it standard or not.The car is a wrx sti import 95.
cheers