Sometimes you need to run a cable longer than 300 feet. In that case, you can either use a POE switch or a POE extender. Using a POE switch you can connect multiple IP Cameras to one switch and then only have to run one ethernet cable back to the network that the NVR is connected to, but you can't plug a POE switch into the NVR directly. A POE extender can be plugged directly into an NVR, but can only connect one camera.
How it works
Direct runs from an NVR’s POE port to a camera can go up to 300 feet without any issues. If a run exceeds this length POE Extenders can be used for a total of 900 feet (max of two POE extenders 300 feet apart).
The POE extenders do not require a separate power source. They will need to be protected if used outdoors.