The M3100E Series 4-Channel 1080p DVR from Flir uses HD-CVI technology, enabling you to upgrade your security system to 1080p HD resolution using your existing coax cabling. With support for both HD resolution MPX cameras and standard analog cameras, the DVR is ideal for retrofit applications. MPX also facilitates advanced features over a coax cable, including duplex transmission for PTZ control, audio transmission, and extended distance cable runs of up to 2300'.