Synchronize events on a segment. 

 | Data byte | Description                                                                                                                                  | 
 | :---------: | -----------                                                                                                                                  | 
 | 0         | Sensor index for a sensor within a module (see [data coding](./data_coding.md). 255 is all sensors. | 
 | 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.                                                                           | 

The sensor index can be used to index units within a module also or used as some other indexing schema. 
