Getting Started with Your HP Notebook Identifying Parts of the Computer Expansion Base – Back 15. Universal serial bus ports (USB). 20. PS/2 mouse port. 16. S-video (TV out) port. 21. PS/2 keyboard port. 17. Serial port (COM1). 18. Parallel port (LPT1). Use this port for a parallel printer or other parallel device. 22. LAN port (works only if the computer has a built-in LAN port). 23. AC adapter jack. 19. External monitor port. 20 Reference Guide