Dell OptiPlex 170L - Manual (Page 62)

14. Connect your computer and devices to electrical outlets, and turn them on.
DC Power Connectors
Small Desktop Power Supply DC Connector Pin Assignments
DC Power Connector P1
NOTE: Your computer's power supply may or may not have the "P7" connector.
Pin Number Signal name 18-AWG Wire
1 +3.3 VDC Orange
2 +3.3 VDC Orange
3 COM Black
4 +5 VDC Red
5 COM Black
6 +5 VDC Red
7 COM Black
8 POK* Gray
9 +5 VFP Purple
10 +12 VDC Yellow
11 +3.3 VDC Orange
12 – 12 VDC* Blue
13 COM Black
14 PS ON* Green
15 COM Black
16 COM Black
17 COM Black
18 N/C N/C
19 +5 VDC Red
20 +5 VDC Red
* Use 22-AWG wire instead of 18-AWG wire.