1. power button/power light
2. USB 3.0 connector
3. optical drive (optional)
4. optical-drive eject button (optional)
5. USB 2.0 connectors
6. hard-drive activity light
7. microphone connector
8. headphone connector
9. optical-drive eject button (optional)
10. optical drive (optional)
11. line-in/microphone connector
12. serial connector
13. power supply unit (PSU) release latch
14. power cable connector
15. hard-drive access cover release latch
16. USB 3.0 connectors
17. USB 2.0 connectors
18. expansion card slots
19. security cable slot
20. padlock ring
21. line-out connector
22. network connector
23. PS/2 Keyboard connector
24. PS/2 Mouse connector
25. active expansion card slots
26. mechanical slot
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