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A digital video recorder (DVR) is an electronic device that records video in a digital format to a disk drive, USB flash drive, SD memory card, SSD or other local or networked mass storage device.A set of 4 channel DVR/NVR can allow you to have 4 individual security cameras connected to the system. This means you can record maximum 4 cameras. We recommend user to buy the video recorders with more channels, which means can allow user to expand the system in the future.A Digital Video Recorder (DVR) records video to local storage devices, most commonly a hard drive. DVR can record analog video sources on-site or capture video from a digital source. DVRs can be connected to analog cameras via coaxial cables, enabling them to be accessed remotely.