Most other alarms are sent from automatic signaling devices, which are installed in many public buildings. These devices include smoke and heat detectors that are wired to send an alarm automatically to an alarm monitoring center. A sprinkler system can also be wired to alert the fire department automatically. Alarm headquarters in a small fire department may consist of one switchboard operator. Most large fire departments have a computerized system of receiving alarms, notifying fire stations, and transmitting data to computer terminals in fire trucks.
Many fire departments have several different types of fire trucks.
Engines have a large pump that takes water from a fire hydrant or other source. The pump boosts the pressure of the water and forces it through hoses. Engines carry several sizes of hoses and nozzles. Many also have a small-diameter hose called a booster line, which is wound on a reel. The booster line is used chiefly to put out small outdoor fires.