This is a Communication Control Block (CCB) parameter. It occupies byte 3 (counting from 0) in the CCB.
| 0 | 300 | |
| 1 | 600 | |
| 2 | 1200 | |
| 3 | 2400 | |
| 4 | 4800 | |
| 5 | 9600 | |
| 6 | 19200 | |
| 7 | 38400 | |
| 8 | 57600 | Only on ARM controllers |
| 9 | 76800 | Only on ARM controllers |
| 10 | 115200 | Only on ARM controllers |
| 11 | 230400 | Only on ARM controllers |
| 12 | 460800 | Only on ARM controllers |
| 13 | 15625 | Only on 32-bit controllers built from 8 Jan 2020 |
Applies to all protocols other than SPLatLink, which is always 9600.