The DMON-QUAD is a compact 4-channel 3G-SDI multiviewer and multiplexer for studios, post houses and other professional video applications. It supports a variety of resolutions and formats up to 1080p60 over SDI and can arbitrarily mix formats and aspect ratios across its four inputs, each of which is independently resolution- and frame-rate-capable thanks to low-latency frame buffering for unsynchronised sources. It supports 3G-SDI level A and B, including conversion between the two, and includes a pass-through mode for an unprocessed signal. Each window carries a 16-character UMD overlay and 8-channel audio metering, individually adjustable for on/off, positioning and size, plus an audio ID overlay. Tally and UMD run over RS-422/485, with tally boxes supporting up to four tallies per window; pre-programmed and custom layouts are both supported, with fast full-screen-scaling switching between inputs. It ships as a standalone unit in a robust aluminium enclosure, with linked HDMI and SDI outputs and updatable firmware.