The DD-DMON-QUAD is a highly portable and versatile 4-channel MultiViewer with HDMI output, designed to support (3G/HD/SD)-SDI formats. This compact device allows for custom layouts, enabling users to display any combination of inputs in various configurations. Each window operates independently, supporting different formats and frame rates simultaneously. The DD-DMON-QUAD features 16 character UMD overlays, 8 channel audio metering, safe action and title overlays, and tally indicators for each window. It also includes a pass-through mode, allowing any of the four inputs to be routed to the HDMI output. The device is equipped with an easy-to-use LCD and button control system, eliminating the need for complex LED/button controls or dip switches. Additional features include 32 GPI on a 37-pin D-SUB connector for tallies and remote switching, RS422/485 for dynamic UMD and tallies via TSL protocol, and a USB port for control and firmware updates. The DD-DMON-QUAD is housed in a heavy-duty metal case with a metal thread locking DC power socket, ensuring durability and reliability in various environments.