But the Wiki article was for '8N1' - that's why I didn't mention it. If you add a parity bit, (say '8E1'), that makes the total 9 bits. When you wrap that in t

But the Wiki article was for '8N1' - that's why I didn't mention it. If you add a parity bit, (say '8E1'), that makes the total 9 bits. When you wrap that in the mark-space pair that makes a total of 11 bits. Then if you have two stop-bits, as in (say '8O2') you have 8 data bits, one parity bit, one start-bit, and two stop-bits. That makes 12 bits altogether for the single data byte sent serially.