16 channel h.264 dvr Video Compression:H.264 ... Support SATA HDD&USB disk RS485 PTZ controller Model16CHVideoInput16 channel, BNC(1.0Vp-p, 75?)StandardNTSC(525Line, 60f/ ... 1 VGA, 1 HDMIAudioInput4 channel, BNC(200-2800mV, 30KΩ)Channel 1 for bidirectional-talk input synchronouslyOutput1 channel, BNC(200-3000mV, 5K ... , 1 for backupRS232Dahua keyboard, PC communicationRS485PTZ control 16 channel h.264 dvr