ATX power supply connector pinout and signals @ pinouts.ru

Here is the pinout for an ATX power supply:


http://pinouts.ru/Power/atxpower_pinout.shtml

Pin	Name		Color	Description
1	3.3V		Orange	+3.3 VDC
2	3.3V		Orange	+3.3 VDC
3	COM		Black	Ground
4	5V		Red	+5 VDC
5	COM		Black	Ground
6	5V		Red	+5 VDC
7	COM		Black	Ground
8	PWR_OK		Gray	Power Ok (is a status signal generated by the power supply to notify the computer that the DC operating voltages are within the ranges required for proper computer operation)
9	5VSB		Purple	+5 VDC Standby Voltage (max 10mA)
10	12V		Yellow	+12 VDC
11	3.3V		Orange	+3.3 VDC
12	-12V		Blue	-12 VDC
13	COM		Black	Ground
14	/PS_ON		Green	Power Supply On (active low). Short this pin to GND to switch power supply ON, disconnect from GND to switch OFF.
15	COM		Black	Ground
16	COM		Black	Ground
17	COM		Black	Ground
18	-5V		White	-5 VDC
19	5V		Red	+5 VDC
20	5V		Red	+5 VDC

/PSON activated by pressing and releasing the power button while the power supply is in standby mode. Activating /PSON connects the power supply’s /PSON input to ground, thereby switching the power supply to full-on condition.