(RPN): An extension to MIDI which allows for additional Control Change messages. RPNs have a Control Change number of 100 (LSB) and 101 (MSB). These are defined in the following way:
Unregistered Parameter Numbers (NRPNs) are vendor-defined and may vary among systems. NRPNs have a Control Change number of 98 (LSB) and 99 (MSB).