4K HDMI USB/Audio/RS232/IR KVM Extender over CAT5e or Fiber Kit - HKM0
HDMI over Cat5e Video Extender w/ RS232 - HDMI® Extenders | Audio-Video Products | StarTech.com
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
us seller NEW HDMI TO DB9 SERIAL VGA RS232 9-PIN ADAPTER CABLE LEAD. Getwiredusa | eBay
HDMI over Cat5 Video Extender with RS232 - HDMI® Extenders | Audio-Video Products | StarTech.com Europe