The following information was deduced by reading the D-Link supplied DNS323 2.6.12.6 kernel source together with empirical reverse engineering.
| GPIO Pin # | GPIO Mask | Direction | Purpose |
|---|---|---|---|
| 0 | 0×0001 | Input | unknown |
| 1 | 0×0002 | Output | right amber LED (= sata ch0 LED) (low-active) |
| 2 | 0×0004 | Output | left amber LED (= sata ch1 LED) (low-active) |
| 3 | 0×0008 | Output | unknown |
| 4 | 0×0010 | Output | power button LED (low-active, together with pin #5) |
| 5 | 0×0020 | Output | power button LED (low-active, together with pin #4) |
| 6 | 0×0040 | Input | unknown |
| 7 | 0×0080 | Input | unknown |
| 8 | 0×0100 | Output | triggers power off (high-active) |
| 9 | 0×0200 | Input | power button switch (low-active) |
| 10 | 0×0400 | Input | reset button switch (low-active) |
| 11 | 0×0800 | Output | unknown |
| 12 | 0×1000 | Output | unknown |
| 13 | 0×2000 | Output | unknown |
| 14 | 0×4000 | Output | unknown - maybe sata ch0 blue LED |
| 15 | 0×8000 | Output | unknown - maybe sata ch1 blue LED |
| 16-31 | unknown - nothing expected | ||
DNS323 rev.C1 has new system board and different MPP/GPIO wiring.
| GPIO Pin # | Direction | Purpose |
|---|---|---|
| 0 | Input | Not connected |
| 1 | Input | Power Key Out |
| 2 | Output | Power Control |
| 3 | Input | AC Power Loss |
| 4 | Input | Not connected |
| 5 | Input | Not connected |
| 6 | Input | Not connected |
| 7 | Input | USB Controller Fault |
| 8 | Input | HDD0 Error |
| 9 | Input | HDD1 Error |
| 10 | Input | Reset button |
| 11 | Output | Power LED Green |
| 12 | Output | HDD0 Link |
| 13 | Output | HDD1 Link |
| 14 | Output | HDD0 Act |
| 15 | Output | HDD1 Act |
| 16 | Output | Power LED Red |
| 17 | Output | Power LED Blue |
| 18 | Output | Fan Control (FULL Speed) |
| 19 | Output | Fan Control (HALF Speed) |
| 20 | Input | Not connected |
| 21 | Input | Not connected |
| 22 | Input | Fan Status |
| 23 | Input | Unknown |
| 24 | Input | Thermal Interrupt |
| 25 | Input | RTC Interrupt |