Baud Rate: Transmission hardware is rated in baud, the number of signal
exchanges per second that the hardware generates. For the RS-232,
The baud rate is exactly equal to the number of bits per second.
Errors: A receiver measures the voltage for each bit multiple times, and
compare the measurements. If the voltages do not all agree or the stop
bit does not occur exactly at the time expected, the receiver reports an
error (Framing Error).
The RS-232 hardware makes use of framing errors by using break to
abort an application. The application interprets the break as a request to
abort ( an error).