Comparison Dahua NVR4216-EI vs Dahua NVR4116-EI

The number of alarm inputs provided in the design of the registrar.

Alarm inputs allow the recorder to respond to various events and signals from other elements of the security system. For example, a door opening sensor can be connected to such an input, and upon a signal from it, the registrar will turn on the camera above this door. This ensures the automation of the security system and makes it less dependent on the human factor.

The number of alarm outputs provided in the design of the registrar.

Alarm outputs are used to transmit signals from the recorder to other elements of the security system — an alarm siren, electronic locks, spotlights, etc. Thus, the system can automatically respond to events recorded by the registrar — for example, block the doors when moving in the frame.

The number of SATA connectors provided in the design of the registrar.

SATA is the most popular modern interface for connecting internal drives. One connector allows you to connect one hard drive (or other internal media), that is, the number of such connectors is, in fact, the largest number of separate drives that can be installed inside the recorder at the same time. Basic versions can be equipped with one SATA connector or two. More advanced ones have 4 SATA connectors, and already models for serious objects have much greater connectivity.

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.