the following is just a general statement, without knowing the specific system that you have; Most window or door contacts are N/O or N/C (Normally Open or Normally Closed) magnetic switches and polarity makes no difference! Your best bet is to contact the manufacturer or distributor. They will give you specific information about the product! (No matter what) :yes::no::yawnon't Drink and Drive!!!bought new winn security contacts for windows to go with alarm system. positive and negative wires are not indicated. how can i tell which is positive and negative?