HOW TO ARRANGE THE CAMERAS? HOW TO CONNECT THEM? WHICH POWER SUPPLY TO CHOOSE?

The issue of arranging your cameras is actually not a technical question but rather a decision regarding your security policy. You must consider what you want to monitor, how important it is to also cover the building surroundings and to what extent, and which areas should be paid a particular attention. Besides, you should think if you would like to have the zoom and object tracing options. When planning the camera layout, take into account the distance to the object to be monitored. An object located within the angle of view but too far from the camera will be unclear, unless your camera has an adequate optical zoom. Please note that the cameras with the PTZ option are not always capable to record a short-lasting event. An excessively long surveillance path and the absence of analytics make it possible to avoid being recorded by the camera.

As regards the connection, it is a consequence of what system you choose. The IP cameras can be directly tied into an already existing LAN, whereas the AHD cameras will require a separate cabling, or you can use the LAN’s twisted-pair cabling. However, it must be separated from the other part of the network. If you use a twisted pair to connect your cameras, you must use the so-called baluns, which will appropriately convert the signal and ensure a physical conversion from a BNC connector (used by the cameras) to an RJ-45 (used by LANs).

 

The IP technology provides an additional option to create a wireless WLAN (WiFi) connection. In this case, you must ensure a good range of the wireless network in the location where the camera is to be installed. Please note that the signal must ensure an adequate speed and must be stable. Otherwise the camera will be unable to properly send the video image to the recorder.

Another case is the power supply. Both the IP and AHD cameras can be powered by feeders connected directly to the camera or by a central power supply system. In the former case, you must provide access to a power socket located close to the camera, which may be impossible, especially in the case of external systems. If you choose a central power supply, the cameras will be connected to a single cable. The cable will be used to transmit data and video signal and to provide power to the cameras. The system powering the IP cameras via a computer twisted pair is called Power over Ethernet (PoE). It is fully standardised, which means that components coming from different suppliers can work together in the same system. A central element in a PoE system is the PoE switch, which is connected to the cameras via the LAN cabling.


PoE power supply on the left, local power supply on the right

In the case of AHD cameras, we can choose between two different solutions. The first one involves a cable connecting two separate lines: a coaxial line for video transmission and a power supply line. The other solution uses a twisted pair and two-function baluns. The baluns provide both video transmission and power supply.


1) Twisted pair
2) Coaxial cable
3) Locally

It should be noted that, in general, AHD cameras are supplied without power units, whereas most IP cameras have them included. The AHD cameras are powered by standardised 12V feeders such as 8level PA12V1.5A.