BigDumbDinosaur wrote:
As Ed noted, TIA-232 is the true “universal serial bus” (though technically not a bus) that makes connecting a wide variety of peripherals a practical matter.
Well, I'd say that the TTY asynchronous start-stop protocol is that. These days probably most serial links are not at all TIA-232 (which requires negative voltages), though they still use TTY async start-stop. (My use of async start-stop at 0V/5V is extensive; my use of TIA-232 is only with my vintage computers that happen to have that port built-in.)