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PC Hardware in a Nutshell, 3rd Edition
book

PC Hardware in a Nutshell, 3rd Edition

by Robert Bruce Thompson, Barbara Fritchman Thompson
July 2003
Beginner to intermediate content levelBeginner to intermediate
874 pages
38h 13m
English
O'Reilly Media, Inc.
Content preview from PC Hardware in a Nutshell, 3rd Edition

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 ...

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Publisher Resources

ISBN: 059600513XErrata Page