Card reader
A card reader is a device for working with removable memory cards. Such media are used to record data, which allows you to save events occurring in front of the calling panel at the right time.
Horizontal viewing angle
Horizontal size of the video panel covered by the camera (see "Type"); this size is most conveniently indicated by the angle between the lines connecting the camera lens with the left and right edges of the scene being viewed.
Theoretically, the wider the viewing angle, the more space the camera is able to cover and the less likely it is that some details will remain out of the frame. At the same time, taking into account the specifics of the use of outdoor panels, it is usually not necessary to equip them with wide-angle cameras; moreover, such optics would be inconvenient due to distortion and reduction effect. Therefore, most models have horizontal viewing angles in the range of 60 – 80 ° — this is quite enough for the intended use.
Vertical viewing angle
The vertical size of the video panel covered by the camera (see "Type"), in other words, the angle between two lines connecting the lens with the top and bottom edges of the scene being viewed. The value of the viewing angles is described in detail above in paragraph "Viewing angles horizontally"; we only note that they are usually smaller vertically than horizontally, and in many models this parameter is not indicated at all because of its secondary importance.
Operating temperature
The operating temperature range of the call panel is the air temperature at which the device is guaranteed to remain operational.
If the panel will be used in a residential apartment, house, office or other premises with similar conditions, you can ignore this indicator: all modern models have a temperature range that is more than sufficient for such conditions. But if the device is planned to be installed on the street, it is necessary to make sure that its operating temperatures correspond to climatic features. It is worth noting here that nowadays panels are produced both for
very cold weather (-30 °C and below), and for
extreme heat(+50 °C and more). A high temperature threshold is also important if the device will be exposed to direct sunlight — under sunlight, the case can heat up to very high temperatures, noticeably higher than that of the surrounding air. And some models combine frost and heat resistance.
