Uses high-speed embedded microprocessor and Linux Operating System 4 and 8 channels optional Video and audio synchronized, real time recording Video compression: H.264 Preview resolution: PAL: 704 x 576 (4CIF), NTSC: 640 x 480 (4CIF) Playback resolution: PAL: 704 x 576 (4CIF), NTSC: 640 x 480 (4CIF) Audio compression: G.726 Supports USB mouse and keyboard control Supports USB HDD video storage backup Supports dynamic domain name Internet interface: RJ45 (10M/100M self adaption) External alarm input: 4 channels