[cctalk] Re: RS232 then and now

A couple of points you might like to consider, which you may already know but stuff you've said above doesn't spell it out: RS232 is not serial - make yourself clear. Before RS232 the same data format was used in current loop (often 20mA or 60mA). RS232 (AKA V.24) is only understandable when you realise it was connecting a terminal (or later computer) to a modem. It's very specific, yet like most technology has been subverted for other purposes. I've kept at last one full RS232 modem in my loft (it was government surplus, and I used to to run a BBS in 1980). Things got weird later, particularly with the Hayes Smartmodem, but modems were dumb devices. The lines went straight through. There were two oscillators (for FM) and the appropriate one was switched in by the TX line being high or low. Likewise the data separator looked for a high or low tone and flipped RX between -12V and +12V. These were all individual boards!