Getting Started with Your HP Notebook Identifying Parts of the Computer Back View 18. Universal serial bus ports (USB). 22. LAN port (on certain models). 19. Infrared port (on certain models). 23. AC adapter jack. 20. External monitor port. 21. Modem port (on certain models). 24. Kensington lock slot (security connector). 25. System-off switch. Reference Guide 15