Dell Precision T3400 (Late 2007) - Manual (Page 14)

14 Quick Reference Guide
Back View (Tower Orientation)
1 power connector Insert the power cable.
2 voltage selection
switch See the safety instructions in the Product Information
Guide for more information.
NOTE: The voltage selection switch is available on the 375-W
PSU only.
3 back panel
connectors Plug serial, USB, and other devices into the appropriate
connector.
1
2
3
4