Audio, Connecting external audio devices, Checking your audio functions – HP 421 Notebook-PC User Manual

Compaq 420 Notebook-PC, 425 Notebook-PC, Compaq 620 Notebook-PC, 620 Notebook-PC, 625 Notebook-PC, Compaq 320 Notebook-PC, Compaq 326 Notebook-PC, Compaq 325 Notebook-PC, 420 Notebook-PC, Compaq 321 Notebook-PC, Compaq 421 Notebook-PC, Compaq 621 Notebook-PC