**Mandatory.** Must be implemented by all devices.

This is the replay sent for events CLASS1.PROTOCOL, Type=40,41. 

 | Data byte | Description | 
 | :---------: | ----------- | 
 | 0 | Index (starts at zero). | 
 | 1 | MSB of page where the register is located. | 
 | 2 | LSB of page where the register is located. | 
 | 3 | Register read/written. | 
 | 4 | Content of register. | 
 | 5-7 | Content of register if multi register read/write. | 

A multi. register read/write can generate up to 256 events of this type. Index will then be increased by one for each event sent. __Some nodes my have small buffers so this bursts of messages may be a problem. Therefore send them with a low priority.__
