Glossary

Open Collector or Relay output. Used as a switch to drive an output with a specified load. Refer to the manual for further details. You can connect a siren, buzzer or magnet actuators, etc.

Contact alarm like a switch. It is used to connect other sensor devices for bi-state signals, such as Open or Close to map door sensor for example.

Serial communication standard. There are many legacy system using RS232/485 communication, such as PTZ cameras. RS232 is bi-directional 1-to1 communication method, while RS485 is bi-directional half duplex 1-to-n communication method. Use 24AWG UTP for RS485 and proper termination is required at the both termination endings or RS485 communication line.

Power over Ethernet. PoE devices like cameras have different classes for different power requirements. During the initial power up, the PoE Hub and the devices negotiates and reserves the power.

Category 5/5e/6 UTP cable, 8 conductor

Ethernet is physical/data link in OSI model. It takes are of data link between two end points. There are different physical medium cush as UTP/CAT5 cables, or Coaxial or Fibers or WiFi.

8 point 8 conductor connector typically used with CAT5/5e/6 UTP cable. Standard Pin out for Ethernet or PoE is specified in T568A, 802.3af.

Only for Box cameras. When cameras are built, they are adjusted to match the lens used in it. While box cameras give you the flexibility to choose different lenses with different focal lengths, it comes at a slightly cumbersome cost, back focusing. A box camera needs to have its back focusing adjusted whenever it is paired with a new lens. You can do this in the lab before installation, or during the installation.

Lens control. Once the field of view is determined for the scene of interest, you need to focus the objects in the scene sharply. Use focus control for this. Make sure that field of depth is related to aperture. When you use auto iris, the installation is done during the day time, when the auto iris is tightly closed, thus giving a deeper field of depth. But during the night time, the auto iris opens up, which narrows the field of view. This results in objects becoming fuzzy and out of focus. Use ND filters during the installation to decrease the amount of light passing through the camera lens, which forces the camera to open up the auto iris, and the depth of field becomes narrow enough to prevent the focus drift during the night or low light condition.

Lens control. Zoom controls the viewing angle, or field of view. Wide gives a bigger field of view, but the objects look smaller in the scene. Tele gives the highest zoom, and gives a narrower field of view. But the objects look bigger in the scene.

Wide Dynamic Range Technology uses two shutter speeds in alternative video fields-high and normal- every 60th (or 50th) of a second and combines two fields into one progressive scan frame. It allows every detail to be captured accurately even if one portion of an image is bright. Whether at the high shutter speed or normal shutter speed, the progressive scan CCD provides a horizontal resolution of 470 lines. As a result, combined fields yield a frame of high-quality images.

The focal length of a lens determines its field of view at a given distance. A wide angle lens as its name suggests a wide field of view at a given distance. This means that it can see a wide area of the scene in both the horizontal and vertical planes. Most lens manufacturers provide tables or charts for their lens providing the necessary data.
f= h x D / H ( h: height of image, D:distance, H: height of Object)

A FOV refers to the maximum angle over which objects are captured on the sensor in a camera. It depends on two factors - the focal length of the lens and the physical size of the sensor. Sometimes, a FOV is called angle of view.
The FOV of a rectilinear lens is calculated using simple trigonometry as following equation.
FOV = 2 x arctan(frame size/(forcal length * 2))
Here, 'frame size' represents the size of the sensor in the direction measured.