This is typically for adjusting the contrast level of a display device 

 | Data byte | Description                                                                                                                                                                                                                                                                                                                                                                | 
 | :---------: | -----------                                                                                                                                                                                                                                                                                                                                                                | 
 | 0         | A value between 0 and 127 indicates the specific contrast level to set. A value between 128 and 159 is change down by the specified number of contrast levels. A value between 160 and 191 is change up by the specified number of contrast levels. A value of 255 means that this is and extended event and that the specific contrast level is sent in byte 3 and after. | 
 | 1         | Zone for which event applies to (0-255). 255 is all zones.                                                                                                                                                                                                                                                                                                                 | 
 | 2         | Sub-zone for which event applies to (0-255). 255 is all sub-zones.                                                                                                                                                                                                                                                                                                         | 
