larryd:
RS232 serial is -V for 1 and +V for 0, TTL is as you have discovered reversed, HIGH for 1 LOW for 0.
Never did liked this.
Definitely not disagreeing.
Funny thing. In all my years of working with RS-232 (which was almost a full time thing between 15 and 20 years ago). I never noticed that.
larryd:
(FYI, RS232 DCD, CTS, DSR are +V for 1 and -V for 0 :o )
Seriously!