> This will only work if the first bit after the startbit is of different 
> polarity from the start bit (don't remember if it is a 1 or 0)

Yes, you're right. An uninverted reception from an NRZ transmitter
will have the Start bit as a logical 1 (0V), so the first bit would need
to be a logical 0 (V+) to measure the Start bit. If it isn't, and a known
pre-amble can't be sent, then you'd have to know the baud rate

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