- Pins 8, and 16 (shaded) are control signals, not power:
- Power on is pulled up to +5 V by the PSU, and must be driven low to turn on the PSU.
- Power good is low when other outputs have not yet reached, or are about to leave, correct voltages.
- Pin 13 supplies +3.3 V power and also has a second thinner wire for remote sensing.[1]
- Pin 20 (formerly −5 V, white wire) is absent in current power supplies; it was optional in ATX and ATX12V ver. 1.2, and deleted as of ver. 1.3.
- The right-hand pins are numbered 11–20 in the 20-pin version.
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