"stop bits"; was: NEC uPD7201 misfeature

Indeed. Consider a wire which is in the marking state, then goes to the spacing state for 312.5 microseconds, returning to mark and staying there for, say, several milliseconds. (I _think_ I'm using `mark' and `space' correctly here; they might need switching. By `mark' I mean the idle state and `space' the other state.) Is that a start bit and two spacing data bits at 9600 baud (with the rest of the character being mark bits) or is it a start bit and five spacing data bits (plus ditto) at 19200 baud? Or is it a framing error at 38400 baud? Or perhaps just a start bit, with all the data being mark bits, at 3200 baud? Or an entire (8-bit) character of spacing bits at 28800 baud? Answer: without more information than just the signal on the wire, there is absolutely no way to tell.