A switch is a device designed to connect and transfer data between multiple network devices, such as personal computers, servers, IP cameras, IP phones and printers. Typically, video surveillance systems use POE switches. Power over Ethernet (POE) technology allows not only information packets to be transmitted over a standard twisted-pair cable in an Ethernet network, but also to supply power to IP cameras, telephones and other network devices. It follows that the main difference between a POE switch and its usual counterpart is the ability to power various IP devices directly through an Ethernet port. POE switch is an ideal solution in cases where it is not possible or desirable to conduct a separate electrical cable to the device. POE technology also eliminates the need to purchase and use an additional, external power source, which is very convenient for the installation and subsequent operation of IP cameras in video surveillance systems. The use of IP cameras and switches with POE support not only simplifies the installation and maintenance of the video surveillance system, but also significantly reduces its cost, which leads to significant savings in financial resources necessary for its construction and further maintenance.
Recommendations when choosing a POE switch. Before you buy a POE Switch for a video surveillance system, you need to remember a few simple recommendations. First of all, before buying, you need to make a decision on a number of organizational issues. Namely:
Determine the location of the DVR;
Approve the number of IP cameras connected to the video surveillance system;
Calculate the distance to the camera farthest from the recorder;
Determine where to install network switches.
When buying a switch, you need to consider that devices of this type can have a different number of ports. For example, the 4 POE ports on the switch allow you to connect up to four IP cameras to it. As a rule, 5 port devices are equipped with so many POE ports, the fifth port of which is designed to connect to a DVR or other network switch. The most common is the switch, which has 8 ports for connecting IP devices. When choosing the number of network switches, it is necessary to consider not only the number of cameras, but also the distance from the server or DVR where they will be located. A maximum distance of 100 meters is allowed. If a group of several cameras are located at a greater distance, it is worth considering the purchase of two or more switches. In situations where a video surveillance system involves the installation of a large number of cameras in a small area, an excellent solution would be to purchase a POE switch for 16 ports.