Serial ports
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  | ### | x | Dir  | Serial port        | Connected serial   | s |
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  |   1 | O |   in | Serial Ctrl 1      | Deck 3             | 4 |
  |   2 |   | auto | Serial Ctrl 2      | Deck 4             | 4 |
  |   3 | L |  out | Deck 3             |                    | 4 |
  |   4 |   | auto | Deck 4             |                    | 4 |
  |   5 |   | auto | Serial 5           |                    |   |
  |   6 |   | auto | Serial 6           |                    |   |
  |   7 |   |   in | Serial 7           |                    | x |
  |   8 |   |  out | Serial 8           |                    | x |
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