Dell Precision Tower 3420 Owner's Manual page 27

11. intrusion switch connector
13. CPU socket
15. memory slot
17. front power-switch connector
19. SD Card Reader (optional)
21. system fan connector
23. USB 2.0 connector
25. 8-pin power connector
27. SATA 2 connector(Black color)
29. service mode jumper connector
31. SATA power connector
33. SATA 1 connector (White color)
35. Debug connector
12. VGA connector
14. CPU fan connector
16. SATA or PCIe SSD Slot
18. debug connector
20. front panel power LED indicator
22. audio connector
24. USB 3.0 connector
26. SATA 0 connector (Blue color)
28. password reset jumper
30. speaker connector
32. internal USB/CLINK header for Intel WiFi
add-in-cards
34. CMOS coin cell battery
36. Thunderbolt connector
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