Comheader
From embeddedTS Manuals
The COM headers follow a legacy pin configuration different from other pin header numberings. The COM headers are numbered thus:
| 1 | 6 |
| 2 | 7 |
| 3 | 8 |
| 4 | 9 |
| 5 | 10 |
Pin 1 corresponds to the pin next to the "dot" on the silk screen.