ATX Optional Power Supply Connector
In addition to the main and auxiliary power connectors, ATX 2.1 defines the ATX Optional Power Supply Connector, shown in Table 26-14. This connector is not required for ATX compliance, but provides various benefits, including fan monitoring and control, a remote 3.3V sense line (used to monitor and correct output on the 3.3VDC line), and a power source for IEEE-1394 (FireWire) devices. This is a 2X3 connector with Pin 1 keyed. The motherboard connector is a Molex 39-30-1060 or equivalent. The power supply connector is a Molex 39-01-2060 or equivalent. All wires are 22 AWG. Wire colors are standard. The first color indicates the base color, and the second the stripe color.
Table 26-14. ATX Optional Power Supply Connector
|
Pin |
Color |
Signal |
Pin |
Color |
Signal | |
|---|---|---|---|---|---|---|
|
1 |
white |
FanM |
4 |
white/black |
1394R | |
|
2 |
white/blue |
FanC |
5 |
white/red |
1394V | |
|
3 |
white/brown |
Sense |
6 |
NC |
Reserved |
ATX Optional Power Supply Connector signals perform the following functions:
- FanM
FanM is a 2-pulse/revolution signal generated by the power supply fan that notifies the system of current fan speed. If this signal drops, the motherboard realizes immediately that the power supply fan has failed, and can shut down the system in an orderly manner.
- FanC
FanC is an optional signal generated by some motherboards to control fan speed for power supplies that are designed to allow this. The signal can range from 0VDC to +12VDC. A signal of +1V or less is recognized by the fan ...