A block lock is used instead of a traditional deadbolt lock on house or apartment doors. This type of lock works via a traditional locking cylinder. The block lock allows you to activate or deactivate the alarm system when you open or close the door. Generally, the door is locked mechanically by turning the deadbolt once. Turning the deadbolt a second time activates the alarm control unit. In order to activate the control unit, information is required as to whether the system is ready for activation, i.e. whether all detectors are closed. If this is the case, a coil in the block lock is supplied with power to allow the deadbolt to be turned a second time. If the alarm system has not granted release for activation, for example because a window is still open, a mechanical block will prevent you from turning the key a second time. The information as to whether the system is ready for activation is transferred to the block lock from the associated alarm control unit. The activation contact in the block lock is also connected to the associated alarm control unit. Similarly, the security area can only be entered once the system has been deactivated via the block lock.