Dahua 5 Series 16 Channel 2 HDD Ai Tech 8 POE NVR (DHI-NVR5216-8P-I_C) - Main Processor: Multi-core embedded processor, Resolution: 16MP, 12MP, 8MP, 6MP, 5MP, 4MP, 3MP, 1080P, 1.3MP, 720P, D1 etc, Storage: Internal HDD: 2 SATA III ports, up to 10 TB for a single HDD. The maximum HDD capacity varies with environment temperature, Audio and Video: IP Camera Input: 16 Channel, Two-way Talk: 1 Channel Input, 1 Channel Output, RCA, Display Interface: 1 x HDMI, 1 x VGA, Alarm input: 4 Channel, Relay Output: 2 Channel, Network Interface: 1 x RJ-45 Ports (10/100/1000 Mbps), PoE: 8 ports (IEEE802.3af/at), 1-8 ports support ePoE&EoC, Auxiliary Interface: USB: 2 USB Ports (1 Rear USB 3.0, 1 Front USB 2.0), RS232: 1 Port, for PC Communication and Keyboard, RS485: 1 Port, for PTZ Control, OS: Embedded LINUX