The second stage is Standard Communication, when the actual CNC movements begin and is initiated by sending the start program byte (0x02). At this point, the PIC will respond with 0x55 to acknowledge it is ready to begin receiving data. This communication consists of a mode byte, followed by additional data (if necessary) or padding if additional data is not required. The mode byte will be one of the values in Table 4-3 and determines how the remainder of the packet is processed.
| Code | Function |
|---|---|
| 0x00 – 0x03 | Standard Movement |
| 0x06 | Home |
| 0x07/0x08 | Raise or Lower Pen |
| 0xFF | End Of Transmission |