Daisy Chain: A daisy chain is a wiring scheme in which hardware devices are connected together in sequence.

Daylight Saving Time(DST): Also called summer time, DST is the practice of moving the clocks forward a certain amount of time from standard time for the purpose of saving energy through more efficient use of the daytime in the summer.

DBMS (Database Management System): A DBMS is a software that controls and manages database, and interacts with a user or an application to access data in the database.

Decryption: The act of recovering encrypted data using decryption keys. Encrypted data can only be decrypted with a symmetric key that pairs with the key used for the encryption of the encrypted data.

Device: An access control device that can be controlled in the BioStar.

Device ID: A unique number given to identify each hardware device in the BioStar.

DHCP: A communication protocol used for the automatic allocation and management of settings required for TCP/IP communication.

Diode: A component that controls the current to flow in a single direction only. This component is used to prevent reverse current flow that momentarily occurs when the door lock operates.

DIP switch: A DIP switch is an On/Off switch that is used to control the behavior of a device circuit board without hardware alteration.

Direct mode: A mode whereby the BioStar 2 client directly searches for connectable devices and connecting to them. In this mode, the client is responsible for communicating with devices and servers. In this mode, a list of connectable devices is shown when a device search is performed on the server, and the administrator can select a device to connect from the list.

Disarm: The act of suspending the operation of an alarm system activated for a specific zone.

Door: A place in which a physical device for access control is installed. A spatial concept that forms the basis for access control.

Door group: A group of doors created for ease of management. Events can be monitored by the door group. A component of an access group.

Door sensor: A sensor that detects the state of the door. There are various types of states such as open, closed, held open, and forced open that can be checked.

Double mode: An authentication method where the credentials of two different individuals are entered in sequence in a limited amount of time.

Dummy Reader: A device that does not store or assess user data, but performs the role of reading credential data such as faces, fingerprints and cards, and transmits this data to the control device.

Duress finger: A fingerprint chosen to generate a certain event upon fingerprint registration. If a user authenticates himself/herself with such a fingerprint, the authentication gets recorded in a log as duress fingerprint authentication. The system administrator can set a separate alarm using the log.