1.1. This HDMI-compatible 4X2 KVM matrix can switch between 4 input signal source devices, distribute the signal to 2 monitors (2 monitors can display the same picture or different pictures), and any one output port can realize independent audio output through Optical SPDIF or 3.5mm audio jack. 2.2. Before using it, please set your two PCs to extended mode to avoid inability to switch. A 4-port KVM matrix can manage 4 computers with two sets of keyboard, mouse and two monitors, and supports various devices with HDMI-compatible interfaces. 3.3. Two different picture signals cannot be displayed on a single monitor. Only one picture can be displayed, and picture-in-picture cannot be displayed on a single display. If two pictures need to be displayed, two monitors must be connected. 4.4. Equipped with 4 USB cables to solve your troubles of buying USB cables, and supports 3 switching modes: button switching, remote control switching, and keyboard switching. 5.5. This HDMI-compatible 4X2 KVM matrix is suitable for entertainment centers, retail and websites, high-definition TV set-top boxes, DVDs, projector factories, data center control, information distribution, meeting rooms, schools and corporate training environments. 6.6. Question: Does the 4X2 device support dual video extension function? The 4X2 KVM device itself cannot be extended with dual video, and your computer needs to support the extension function. For example, if the computer has an expansion card installed, it will support dual video expansion. (Note that the computer needs to have a computer expansion card installed) 7.7. Before using it, please set your two PCs to extended mode to avoid inability to switch.