An IP CCTV system is easier to plan once you understand the job of each component. The cameras capture video, the network carries it, the NVR manages and records it, and a compatible hard drive stores the footage for later playback.
What is an NVR?
NVR stands for network video recorder. It receives video from compatible IP cameras over a network, displays live views and records footage to installed storage. It also manages playback, user access and many detection or notification settings.
The number of channels tells you how many camera streams the recorder is designed to manage. A four-channel NVR normally supports up to four cameras, while an eight-channel model provides room for a larger system. Channel count is not the only limit: check supported resolution, incoming bandwidth, decoding performance and compatibility as well.
What is PoE?
PoE means Power over Ethernet. A PoE connection can carry both electrical power and network data through one compatible Ethernet cable. This reduces the need for a separate power outlet at every camera position.
Some NVRs have built-in PoE ports, allowing cameras to connect directly to the recorder. Other systems use a separate PoE switch. Confirm the required PoE standard and power budget, especially for cameras with heaters, powerful infrared lights or pan-tilt-zoom motors.
Why use a surveillance hard drive?
CCTV recorders can write video for many hours every day. Surveillance-rated hard drives are designed for this type of workload and for multiple video streams. The drive must still be supported by the NVR, correctly installed and formatted through the recorder.
Some CCTV packages are sold without a hard drive so the buyer can choose the capacity. “No HDD” means live viewing may be available but recorded playback will not be stored until compatible storage is installed and configured.
How much storage do you need?
There is no single storage capacity that suits every system. Retention time is affected by:
- number of cameras;
- resolution and frame rate;
- H.264 or H.265 compression settings;
- continuous or event-based recording;
- scene activity and image-quality settings; and
- audio recording, where enabled.
Manufacturer storage calculators can provide an estimate, but final results vary with the actual configuration. Leave some margin rather than selecting a drive that only meets the most optimistic estimate.
Compatibility checks before purchase
- Confirm the NVR supports the camera model or the required network protocol.
- Check the maximum supported camera resolution and bandwidth.
- Confirm whether PoE ports are built in or a separate switch is required.
- Check the number of drive bays and supported capacity per bay.
- Use current manufacturer documentation for firmware and feature compatibility.
Example system layout
In a straightforward four-camera PoE system, each camera connects by Ethernet cable to a PoE NVR. The NVR connects to a monitor for local viewing and to the router for authorised remote access. A surveillance hard drive installed in the NVR stores the recordings.
A larger or more flexible network may place the cameras on one or more PoE switches, with video travelling across the network to the NVR. Network design, switch capacity and security become more important as the system grows.
Compare complete CCTV packages or browse networking and PoE equipment. If you are unsure about compatibility, send us the model numbers before ordering.