CCTV, AHD, and HD-TVI. Users may configure each channel for any of these camera types. For example, you may have an analog CCTV camera connected to channel one, a 720p AHD camera connected to channel two, a 1080p AHD camera connected to channel three, and a HD-TVI camera connected to channel four (720p and 1080p is also supported for HD-TVI cameras). These hybrid CCTV DVRs are the best choice for users that have existing standard definition CCTV cameras and want to upgrade to high definition surveillance cameras.