Col> A bit whiCh signals the start of transmission of a CharaCter on a serial line. For an RS-423 signal, the line is normally at logiCal zero whiCh there is no data and the start bit is a logiCal one. The zero-one transition tells the reCeiver when to start sampling the signal to extraCt the data bits. [Is this upside-down?] (1995-02-02)