Freetserv: a free serial terminal server 11 years ago
This is currently under development but need some funding.
https://www.nexlab.net/product/rasky/
Rasky is a low cost open source (hardware and software) KVM over IP built on top of the well known RaspberryPI model 2B featuring VGA video capture, USB keyboard and mouse emulation, remote control both by web (ajax VNC) and VNC, remote relay switches and digital inputs.