Table 228

+=========-==================+ 
|   Code  |  Pacing protocol | 
|---------+------------------| 
|    0h   |  None            | 
|    1h   |  XON/XOFF        | 
|    2h   |  ETX/ACK         | 
|    3h   |  DTR             | 
| 4h - 7h |  Reserved        | 
| 8h - Fh |  Vendor-specific | 
+============================+