This allows the dispatcher to give the exact location and device type to responding personnel. Having multiple personnel available to respond to incidents also reduces response time. The number of personnel available can be significantly increased by combining the efforts of fire and security personnel for response to fire incidents. This may be a simple matter of coordinating radio frequencies for the two groups. There are also methods for reducing the effect of any delays created by the presignal system arrangement.
Most building codes require that voice alarm systems be installed within airport terminal buildings.
Pre-recorded or live voice messages are transmitted from a central location, typically from the communications center. Building occupants tend to respond more orderly, and with less delay, to voice systems rather than bells or horns. This type of evacuation system also permits specific instructions to be given to individual areas of the building. This allows occupants to be directed away from the immediate danger area, prevents occupants from egressing toward the area of danger, reminds occupants elevators are not in service and has many other advantages by permitting the tailoring of messages to each incident. Another special area of concern for notification of building occupants is that of air traffic controllers.