4K HDMI USB/Audio/RS232/IR KVM Extender over CAT5e or Fiber Kit - HKM0
Avenview 4x1 HDMI Switcher with IR and RS232 Control SW-HDM-4X1
10ft/3m USB to RS232 Serial Adapter - Serial Cards & Adapters | Add-on Cards & Peripherals | StarTech.com
USB to RS232 Adapter with PL2303 Chipset, CableCreation 6.6 ft USB 2.0 Male to RS232 Female DB9 Serial Converter Cable for Cashier Register, Modem, Scanner, Digital Cameras, CNC,Black - Walmart.com
HDMI Switch 16 Port 4K 60Hz Auto Switch With RS232/LAN-TESmart
HDMI/RS232 100m Extender Kit, HDBT, 4K/60 – Muxlab Dealer Portal
Amazon.com: SIIG 4K HDR HDMI 2.0 HDBaseT Extender Over Single Cat5e/6 with RS-232 & IR - 330ft (100m) @ 1080p & 3840x2160@60Hz YUV 4:4:4 8bit, RS232, HDMI 2.0 and HDCP 2.2, HDR,
4K HDMI with RS 232 data over Optic Fiber Extender – Transwan
Pro AV/IT Integrator Series™ HDBaseT 3.0 HDMI 4K 60Hz 4:4:4 with USB
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