This European Standard provides for security grades 1 to 4, (see EN 50131-1) specific or non-specific wired or wire-free lock state contacts, and includes the requirements for four environmental classes covering applications in internal and outdoor locations as specified in EN 50130-5. Lock state contacts are installed in windows or doors and windows or doorframes to allow to monitor the lock/unlock status only or the lock/unlock status combined with the open/close status of a window/door simultaneously and are as such located in supervised premises. They provide the necessary range of signals or messages to be used by the rest of the intrusion alarm system. A detector fulfils all the requirements of the specified grade. Functions additional to the mandatory functions specified in this European Standard may be included in the detector, providing they do not influence the correct operation of the mandatory functions. The combination of the two separate units of the lock state contact is referred to in the body of this European Standard as the detector.