Hey gang, a few months ago I had found the 1968/1969 document spec of RS-232. But now, I'm unable to find it again !
At Internet Archive, there is one link/reference to it, but it appears to just be the cover page (which does have the date of August 1969). I see the EIA RS-232-C spec dated from 1991 (but I think that date is just marking when EIA took over stewardship of the standard, but the spec should reflect/match the original 1969 one). In the manual for the DataSet 103C (from a few years earlier than 1969), it outlines signal lines all labeled like RS-232. But I wouldn't call it an RS-232 spec. Like most standards, it takes a number of years for a community/critical mass of products to understand it and adopt it correctly. Even ASCII wasn't globally recognized and adopted until maybe 15 years after it was introduced? So I was trying to track down the "earliest mention" of RS-232, to pinpoint it really being from 1962. Technically it appears the EIA "guards" that spec, and makes it expensive to officially download it. Maybe they took an initiative to try to scrub earlier editions from the public web, maybe that's why it's harder to find now? But I was pretty sure I found a scanned copy of it at some point (the Aug 1969 one). If anyone happens to have a printer version (of a 1969 or earlier RS-232 spec) - it would at least be nice to know that exists somewhere. I'm pretty sure that "original spec" called out +/- 3 to 25V, later ones maybe used 20V or 15V. -Steve
