Actually, I had learned that baud rate referred to the number of [i]data elements[/i] that were sent in one second. A data element was defined as one of the distinguishable states (signal changes) of the data line. In wired RS-232 you only have two states: the voltage polarity of the data line, so one baud equals one bit (of whatever...data, parity, start bit, etc.).

In modems however, things can get different because there can be more then two signal states. Simple modems like 300 and 1200 bps models use frequency shift keying with only two frequencies, so one bit = one baud. With encoding techniques such as QAM (Quadrature Amplitude Modulation), the signal amplitude and phase angle of the carrier can all be varied. A 14400 Bps modem is actually sending only 2400 signal changes per second. The signal can have one of 8 phase angles and one of four amplitudes, for a total of 32 possible states. This allows 6 bits to be encoded into each one of the 32 combinations of phase angle and amplitude. Thus a 14400 bps modem is operating at 2400 baud.