Manual fire alarm activation is the process of triggering a fire alarm through a call point, pull station, or other device. This usually causes the alarm to sound the evacuation signal for the relevant building or zone. Manual fire alarm activation requires human intervention, as distinct from automatic fire alarm activation such as that provided through the use of heat detectors and smoke detectors. It is, however, possible for call points/pull stations to be used in conjunction with automatic detection as part of the overall fire detection and alarm system. Systems in completed buildings tend to be wired in and include a control panel. Wireless activators are common during construction. When a fire pull station or call point is activated, codes usually require evacuation begin immediately. There are certain exemptions like system maintenance and security lockdowns, where manual activation outside the control panel may be overridden. Security alarms, emergency door releases, industrial fire suppression systems, and hazardous material leak alarms are all examples of specialty systems which are sometimes activated with similar manual initiating devices to a fire alarm. They may be linked to fire alarm systems to varying degrees. Fire alarm pull station A fire alarm pull station is an active fire protection device, usually wall-mounted, that, when activated, initiates an alarm on a fire alarm system. This is the most common design in North America. In its simplest form, the user activates the alarm by pulling the handle down, which completes a circuit and locks the handle in the activated position, sending an alarm to the fire alarm control panel. After operation, most fire alarm pull stations must be restored to the ready position using a special tool or key for the panel to be reset. Primitive manual stations, requiring only a single action or hand motion to activate, can be subject to unwanted activation by jarring or accidental contact. Early strategies to cope with this problem included requiring the operator to break a pane of glass to release an internal spring-operated mechanism. Manual pull stations that require two hand motions, such as lift up and pull down, or push in and pull down, have since replaced the break-glass and single-action models in many modern installations. Coded pull stations In the past, pull stations controlled the entire system. These coded pull stations were much bigger than modern pulls and had a code wheel in them. They had a