... image quality adjustable ,three optionPreview resolution: Host code: 4 channel H.264 D1(NTSC 720X480/PAL 720X576)/ 120 pcsTransmission code ... , HDD optionRecord mode: Manual , alarm ,timed Audio intercom : One channel BNC Two-way intercom, aideo code G.72X, bit code 8kbpsNetwork Protocal ... , control, playback, PTZ control and video.UHF Can be used separately, also can combine with 3G H.264 DVS to ...