Camera connection
Possibilities for connecting cameras available in the registrar.
For analogue DVRs and digital NVRs (see "Type") in this case, everything is simple: the number of video channels corresponds to the largest number of incoming video signals that can be connected to the device. Such a signal can come both from a camera and from an intermediate device — for example, a quad that combines a picture from 4 cameras. But in hybrid HVRs, the meaning of this paragraph is more specific. For these recorders, this specifies the maximum number of inputs that the device can handle in AHD only mode (i.e., analogue cameras only, no IP cameras). Data on hybrid mode (AHD+IP), as well as for using only IP cameras, are given separately for such recorders (see below).
Numerous channels (
32 channels,
64 channels and even
128 channels) allows you to create an extensive video surveillance system based on the registrar without using additional equipment (for example, the same quads). On the other hand, this characteristic significantly affects the price, and for living conditions,
registrars for 4,
8 or
16 cameras are quite enough.
Hybrid mode (AHD+IP)
The number of cameras supported by the recorder when operating in hybrid mode — that is, when using traditional (AHD) and network IP cameras at the same time. For details about hybrid recorders, see "Type". And in this paragraph, the first number indicates the number of conventional cameras, the second — IP devices: for example, the entry "4 + 2" indicates that this model can simultaneously receive a signal from 4 conventional and 2 IP cameras.
Also note that some hybrid recorders allow different ratios between the number of cameras of different types (with the same total number of cameras). For example, a 12-channel model may have 6+6, 8+4, and 10+2 hybrid modes. In such cases, this paragraph takes into account the mode with the largest number of AHD cameras; for the model described in our example, “10+2” will be written in this paragraph.
It is also worth mentioning that when working only with IP cameras, the hybrid recorder can support a greater number of video channels than in hybrid mode — for example, in the “2 + 8” format model, the number of supported only network cameras can reach 16. This information is specified in "IP Only".
IP only
The number of cameras (video channels) supported by the hybrid recorder (see "Type") when working with IP cameras only.
Most often, this number corresponds to the total number of channels available in hybrid mode (when IP cameras are combined with traditional, so-called AHD cameras). For example, for a DVR with 8+2 hybrid mode (10 in total), the number of cameras in IP only mode is also usually 10. However, there are exceptions: some models in pure network mode are able to work with more cameras than in hybrid. For example, the same hybrid format "8 + 2" can be combined with support for 16 or even 24 network cameras at the same time.
BNC video input
The number of
BNC inputs provided in the design of the registrar.
BNC — connector with bayonet fixation for coaxial cable, used including for transmission of analogue video signal in professional equipment. In registrars, inputs with such connectors are used to connect analogue cameras. The more connectors, the more analogue cameras can be connected directly to the registrar at the same time; and in DVR devices (see "Type"), the number of BNC inputs corresponds to the number of channels.
Bandwidth
The maximum data stream in Mbit/s that the NVR is capable of processing when recording and displaying. The throughput parameter is specified as the maximum incoming/outgoing speed, or as the sum of incoming and outgoing streams (total throughput). It is calculated in such a way that the throughput exceeds the total flow of all IP cameras connected to the DVR, and another 25–30% is put in reserve for playing video or viewing it via network access.
Max. total capacity
The largest total storage capacity with which the recorder is able to work correctly. By default, it is indicated only for internal media with a SATA interface (see above), however, in some models, data is also provided separately for external devices connected via eSATA.
Note that the limit on the total capacity follows from the fact that each individual port has its own limit on the capacity of the drive. In this case, the maximum capacity is distributed equally between the ports. This should be taken into account when choosing drives for the registrar: for example, in a 32 TB model with 8 SATA connectors, the limit for each connector will be 32/8 = 4 TB. This means that installing two internal 8 TB disks in such a registrar will not work, although their total capacity will be less than the maximum.
