V.superduperfast is a figment of your imagination. Just remember to look for one of the above three labels when buying your modem. After three months, soething better, faster, and cheaper we be out and you will kick yourself for not waiting. 28,800 bps is about as fast as one can push bits through a conventional phone line. The bandwidth of an analog phone line has a theoretical limit which we are fast approaching.
Modems transmit information by signal changes.
Each change may represent more than one bit of information. If one bit is encoded with each signal change, then baud rate is equal to the bits per second. Well that's as clear as mud. Better to speak in terms of bps, since that's the important number. I described earlier.