In the world of MIDI, temperament is used as system of tuning. However, many ethnic music scale contains notes which are not fit into temperament. For example, if you need a note between "C" and "D", then you will have "C#." However what will you do if you need to have a note between "C" and "C#?" How do you generate this sound with MIDI? There are two ways to do this. One is to use tuning table and another is to use pitch bend command. To change tuning table, a System Exclusive Command can be used. The System Exclusive Commands are different from maker to maker (Ex, GS and XG), different data must be used for different sound devices. If you use pitch bend command, then there are no differences from maker to maker. But pitch bend command is not for tuning originally. Many sequence soft assume pitch bend of 1/4 or 1/2 note usually.

Tuning tool

Links to MIDI and Tuning site