In a CCTV system, the DVR (or Digital Video Recorder) is the central processing unit upon which the entire system depends.
The DVR takes inputs from the cameras and other sources – such as an installed alarm or microphones – and records video and images to a built-in HDD (Hard Disk Drive). The DVR also displays the system status on an attached monitor or HD TV. And the recorded data can be on-sent or streamed by several means to remote locations.
With a large HDD, a DVR can record and store months of video. This video can be downloaded onto a USB stick for use as evidence or to give to police or other enforcement agencies. It can also be backed up across a network so that the data is kept indefinitely.
DVRs fall into three categories; Analogue, HD and more recently, Hybrid. An analogue DVR can only receive input and record data from analogue cameras. An HD DVR can only accept input from the newer HDSDi cameras, but cannot accept analogue input.
A Hybrid DVR, however, can as the name suggests receive data from both analogue and HD cameras, making it ideal for using when newer HD cameras are added to an existing system which still utilises some analogue cameras.
DVRs usually come with the ability to connect 4, 8, 12 or 16 cameras at a time. While your current system may only have 2 or 3 cameras, it is wise to plan for expansion and outlay the extra $$ for additional inputs, because this isn't something that can be added later.
The cheapest DVRs are Analogue, followed by HD and the most expensive are Hybrid. But the size and quality of the internal HDD can make a huge diffeence to the overall price. Because data files get exponentially larger with higher quality cameras, larger capacity (more expensive) HDDs are required for HD systems, which exacerbates the price difference.
This is a very quick introduction to what is a DVR. For more information, we suggest you research online, or you can contact us with your questions.