Date/Time Generator
Installed between a CCTV camera and a monitor, it generates the information of Date, Time and camera ID.
DC Power
Direct Current Power; can be derived from an AC adapter or from a battery. Among DC voltages of 6, 9, 12, 24, 28, 12VDC is most common in the CCTV industry.
Decibel (dB)
The power or voltage ratio of two signals.
DFP
Digital Flat Panel, one of digital video connectors.
DIP switches
Dual Interface Poll switches usually allow you to change the configuration of a circuit board to suit your application.
DMZ
Detection of Motion Zone
DHCP
Dynamic Host Configuration Protocol; lets network administrators manage centrally and automate the assignment of IP addresses in an organization's network.
DIN
Multi-wire cable with DIN connectors at both ends. Usually has 5 or 6 inner wires. Different diameter and configuration from maker to maker. Pictures of DIN connectors or, more details about DIN Cable.
Distortion
A general term when the object is not shown exactly as is.
DNS
1)Domain Name System. A general purpose distributed, replicated, data query service. Its principal use is the lookup of host IP addresses based on host names.
2)Domain Name Server. A computer that converts host names, such as www.pelikancam.com to its corresponding IP Address, such as 67.100.253.111
DRAM
Dynamic Random Access Memory. Most common RAM (Random Access Memory) for PC.
DSL
Digital Subscriber Line. A technology for bringing higher-bandwidth information to homes and businesses over ordinary copper telephone lines.
DVI
Digital Video Interface, one of digital video connectors.
DVR
Digital Video Recorder; records video pictures digitally.
Dwell Time
The length of time a switcher displays one camera before sequencing to the next.
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.
Door Forced Alarm
An alarm generated when a door is forced open, opening the door switch contact.
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.
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.
