DVR
Automatic Gain Control (AGC)
Some cameras are equiped with an AGC circuit. This circuit examines the brightness level of the video signal to keep it at a consistent level. For example, if the video signal is dark, it will attempt to increase the gain to bring the brightness up to a normal level.
Aperture
In CCTV optics, the aperture is the diameter of the lens that controls the amount of light reaching the image sensor. It is shown by an f-number. Larger aperture lenses have smaller f-numbers. For instance, a lens with an f-number of 1.2 will allow more light to reach the sensor than a lens with an f-number of 2.0 thus producing a brighter image.
Auto Iris Lens
An automatic iris lens is a lens with a motorized iris that automatically adjusts to only allow a specific amount of light to reach the image sensor. When there is little light, the iris will open to let more light in. When there is too much light, the iris will close to reduce the amount of light let in. Auto iris lenses are primarily used in applications where light levels vary and it would be impracticable to manually adjust the lens. Automatic iris lenses are generally more efficient than the electronic shutter since they actually control the amount of light reaching the sensor as opposed to simply adjusting shutter speed.
Monitor, Observation Set
IR Illuminator
Controller
Quad, VCR
Video Door Phone,
Time & Date Generator
Time & Date Generator
High resolution camera is a camera that displays an image that consists of 480 horizontal TV Lines. The highest Color image is typically 500TV Lines and the highest B&W 600TVL. Those cameras that feature more than 480 TV Lines, such as our DNC-540H that feature 530 TV Lines, produce images that are somewhat digitized if anything since they have the same effective image pixels as 480 TV Line cameras. Therefore the quality difference is barely noticeable. For that reason, many color cameras these days spec their resolution at 520TVL anyways.
PoE (Power over Ethernet)
Power over Ethernet or PoE technology describes a system to transmit electrical power, along with data, to remote devices over standard twisted-pair cable in an Ethernet network. This technology is used not only for powering IP Cameras but also IP telephones, wireless LAN access points, remote network switches, embedded computers, and other appliances where it would be inconvenient, expensive or infeasible to supply power separately. In order to use PoE on IP cameras, the cameras must be PoE-manageable, and the network area in which the IP cameras are to be installed has to have PoE device, such as PoE hub or switch.
Stand-Alone DVR
A Stand-Alone DVR is an all-in-one DVR and Multiplexer/Quad. Typically, though not always, A Stand-Alone DVR has push buttons or/and comes with IR remote controller, and no Mouse or Keyboard. They have an Embedded Operating System (embedded on chips, not installed in the HDD as PC-Based DVR) and are generally non Windows. Most are Embedded Linux and some more expensive ones use an Embedded RTOS (Real Time Operating System). This means they do not run on standard PC Components, but specially built or modified components for their purpose. Because of these facts, they are not affected by common Windows virus or Windows-crash, and therefore known to be more stable. On the other hand, the general features and operations of a Stand-Alone DVR are generally inferior to a Windows based DVR.
