Start and Stop Bits
When the Data Line is at Rest
- It is kept in the “1” state
- So “11110000” would look like 111111100001111
- “00001111” would also look like 11111100001111
How can you tell where a character begins?
- Add a start bit (always 0) to change the line state
- End with a stop bit (always 1) to guarantee at least a one-bit rest (1) against which to detect the next start bit (0)