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).