Serial Ports
Many of my devices connect to my desktop system via a StarTech PEX8S952 8-port serial adapter, which is ttyu2 to ttyu9.
My TS-940S has the control interface on the first port (ttyu2), and a separate port (ttyu9) which has PTT, CW keying, and FSK. It’s connected via my home-brew Ultimate TS-940S Interface.