Figure 1-5. Expansion Base — Back View 15. Universal serial bus ports (USB). 20. PS/2 mouse port. 16. S-video (TV out) port. 17. Serial port (COM1). 21. PS/2 keyboard port. 22. LAN port (works only if the computer has a built-in LAN port). 18. Parallel port (LPT1). Use this port for a parallel printer or other parallel device. 19. External monitor port. 23. AC adapter jack. 1-6 Product Information HP Omnibook 500