On Fri, 31 Jan 2025, Chuck Guzis via cctalk wrote:
As far as RS232 and history, I submit that current-loop has more of a place in telegraphy, as it's far more suited to long distances and is less susceptible to signal noise. Many early 1970s serial interfaces offered the choice between 20ma or 60ma current loop or RS232C.
up to the 5150 "Asynchronous Communication Adapter"The "free" serial adapter used by IBM to discourage use of the eighth slot was probably the same one.
