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Contents
Connectors
CAUTION Only the back panel USB, front panel USB, VGA, and PS/2 connectors have overcurrent protection. The Desktop Boards' internal connectors are not overcurrent protected and should connect only to devices inside the computer's chassis, such as fans and internal peripherals. Do not use these connectors to power devices external to the computer's chassis. A fault in the load presented by the external devices could cause damage to the computer, the interconnecting cable, and the external devices themselves.
This section describes the board's connectors. The connectors can be divided into the following groups:
Note: When installing the board in a microATX chassis, make sure that peripheral devices are installed at least 1.5 inches above the main power connector, the diskette drive connector, the IDE connector, and the DIMM sockets.
Back Panel I/O Connectors
The figure below shows the location of the back panel connectors. The back panel connectors are color-coded in compliance with PC 99 recommendations. The figure legend below lists the colors used.
| Item |
Description |
Color |
| A |
PS/2 mouse port |
Green |
| B |
PS/2 keyboard port |
Purple |
| C |
USB ports |
Black |
| D |
Serial port A |
Teal |
| E |
Parallel port |
Burgundy |
| F |
LAN (Optional) |
Black |
| G |
USB ports |
Black |
| H |
Audio line in |
Light blue |
| I |
Mic in |
Pink |
| J |
Audio line out |
Lime green | |
Integrator's Note: The back panel audio line out connector is designed to power headphones or amplified speakers only. Poor audio quality occurs if passive (non-amplified) speakers are connected to this output.
Internal I/O Connectors
The internal I/O connectors are divided into the following functional groups:
Audio, Power, and Hardware Control Connectors
The figure below shows the location of the audio, power, and hardware control connectors.

| Item |
Description |
| A |
Front panel audio |
| B |
ATAPI CD-ROM (black) |
| C |
+12 V power connector (ATX12V) |
| D |
Rear chassis fan |
| E |
Processor fan |
| F |
Main power |
| G |
Front chassis fan |
| H |
Chassis intrusion | |
Add-in Board and Peripheral Interface Connectors
The figure below shows the location of the add-in board connector and peripheral connectors for the Desktop Board D845EPI. Note the following considerations for the PCI bus connectors:
- All of the PCI bus connectors are bus master capable.
- SMBus signals routed to PCI bus connector 2, enabling PCI bus add-in boards with SMBus support to access sensor data on the Desktop Board. The SMBus signals are as follows:
- The SMBus clock line is connected to pin A40.
- The SMBus data line is connected to pin A41

| Item |
Description |
| A |
PCI bus connector 3 |
| B |
PCI bus connector 2 |
| C |
PCI bus connector 1 |
| D |
AGP Connector |
| E |
Diskette drive |
| F |
Primary IDE |
| G |
Secondary IDE | |
Integrator's Note: Not all PCI video cards can be used in PCI bus connectors 1 and 2 (the PCI bus connectors closest to the processor). To avoid clearance problems, install PCI video cards in PCI bus connector 3.
External I/O Connectors
The figure below shows the location of the external I/O connectors.
| Item |
Description |
| A |
Serial port B (optional) |
| B |
Auxilary front panel power/sleep/message-waiting LED |
| C |
Front panel |
| D |
Front panel USB | |
Front Panel Connector
This section describes the functions of the front panel connector. The table below lists the signal names of the front panel connector. The figure below is a connection diagram for the front panel connector.
Front Panel Connector
| Pin |
Signal |
In/Out |
Description |
Pin |
Signal |
In/Out |
Description |
|
Hard Drive Activity LED |
Power LED |
| 1 |
HD_PWR |
Out |
Hard disk LED pull-up (750 ohm) to +5 V |
2 |
HDR_BLNK_GRN |
Out |
Front panel green LED |
| 3 |
HAD# |
Out |
Hard disk active LED |
4 |
HDR_BLNK_YEL |
Out |
Front panel yellow LED |
|
Reset Switch |
On/Off Switch |
| 5 |
Ground |
|
Ground |
6 |
SWITCH_ON# |
In |
Power switch |
| 7 |
FP_RESET# |
In |
Reset switch |
8 |
Ground |
|
Ground |
| 9 |
+5 V |
Out |
Power |
10> |
No connect |
|
Not connected | |

Front Panel USB Connector
The figure below is a connection diagram for the front panel USB connector.
Integrator's Note:
- The +5 DC power on the USB connector is fused.
- Pins 1, 3, 5, and 7 comprise one USB port.
- Pins 2, 4, 6, and 8 comprise one USB port.
- Use only a front panel USB connector that conforms to the USB 2.0 specification for high-speed USB devices.
 For more information about the front panel connector, see the Product Supplement Document for the Intel® Desktop Board D845EPI
This applies to:
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