ACCESS CONTROL TERMS D
Database: A collection of data used and produced by a computer program. The files created at the host of the access control system forms its database.
Dedicated I/O Point: An input or output that is dedicated to a specific function. Often, dedicated input points can be assigned to initiate tasks such as an Auxiliary RTE, and a dedicated output point can be assigned to initiate tasks such as the annunciation of Door Forced or Door Held Open alarms.
Dedicated Telephone Line: A telephone line directly connecting two points. Also Known As - Lease Line.
Degausser: A device that creates a strong magnetic field that erases data from magnetically encoded media such as magnetic stripe cards.
Degraded Mode: A mode of controller operation that provides a minimal authorization level in the event of controller failure.
Device Address: Value set on an access control device to determine its unique identity.
Distributed Access Control: Access control systems in which all control decisions are made at the local controllers, independent from a host computer. Local Controller events are uploaded to a host computer periodically for review and storage.
Distributed Intelligent Devices: Access control devices that make
their own access decisions uploading event messages periodically to the central processing unit for storage.
Distributed processing: An access control system where some of the system information is stored at the individual readers or controllers. This allows the system to operate when the host is down or not communicating.
Door: A generic term for a securable entry way. In many access control applications a "door" may actually be a gate, turnstile, elevator door, or similar device.
Door Forced Alarm: An alarm generated when a door is forced open, opening the door switch contact.
Door Held Open Alarm: An alarm generated when a door is held open beyond the a designated period of time (as programmed by access control software).
Door Held Open Time: The amount of time from when a door is opened before an alarm is generated for the door being opened too long. This is often used to monitor if a door is being propped open following a valid access request.
Door Switch: A switch that reflects the state of the door: if the door is open, the switch is open -- if the door is closed, the switch is closed.
Download: Sending information from a host computer to a peripheral device in an access control system.
Duress: Forcing a person to provide access to a secure area against that person's wishes.
Duress Alarm: A device that generates a silent alarm signal in the event a person is experiencing Duress. This device may be a standalone signaling device or it may be incorporated into a reader.
Duress Code: An alphanumeric code which, when entered into an access control system, alerts the system to a Duress condition.
Duty Cycle: The ration of system ON time to system OFF time.