HP ProBook 4320s, 4321s, 4420s, and 4421s Notebook PC

Right-side components
Component Description
(1) USB ports (2) Connect optional USB devices.
(2) RJ-11 (modem) jack (select models only) Connects a modem cable.
(3) Optical drive light (select models only) Blinking: The optical drive is being accessed.
(4) Optical drive (select models only) Reads optical discs and, on select models, also writes to optical
discs.
16 Chapter 2 External component identification