DVR is technical terms used to describe Digital Video Recorder,
which is kind of multimedia digital data processing and storage system widely applicable in security industry. DVR includes most of all functions available in former analog recording system, such as a tape recorder, VCR, or time lapse recorder. Further DVR has a function of remote monitor and control over the network, data transmission, and image search in digital way, which we could not even imagine in conventional type of surveillance equipment.

Most cameras are analog and must be converted to digital picture. Any standard camera will give you a nice picture because again, the technology
can not take any real advantage in picture quality at this time. However,
we recommend you to choose best suitable cameras for AVS DVRs to transmit high level of resolution which will match with the performance of AVS DVRs.

There are several important things to look at when buying a DVR.
The first is the interface. Is it easy to operate?
AVS non-PC-based DVR is designed in such a way that any users familiar
with consumer PCs to some extent can operate without mistake.
The second would be the reliability of the system.
AVS non-PC based DVR excluded PC and OS, and it is very stable and reliable in operation. Another thing to look at is the frame rate(fps), and it may be the most important parameter evaluating performance of a DVR.
This relates to how many pictures it display and record in a second.
channels at very high resolution.

A VCR has a low resolution level, and it causes the picture to be grainy.
The video tapes degrade and decompose within a short time and video head wear out after long-term use. With a DVR you don't need to change tapes or touch the system at all for long periods of time. The only moving parts is the hard disk drive and if a part breaks, you can easily replace it form the local computer store.

Monitor for CCTV or TV also possible to use

It depends on the transmission way.