HDMI over Cat5e Video Extender w/ RS232 - HDMI® Extenders | Audio-Video Products | StarTech.com
HDMI Extender Power over Ethernet PoE up to 230ft with bi-directional IR and RS232
Amazon.com: KVM Switch with Serial Port Control, 4K@60Hz 4 in 1 Out HDMI KVM Switcher Box for Share Mouse Keyboard and Monitor, Can Work with Pi-kvm, Compatible with Windows/Linux/Mac System : Electronics