The sound system for the PowerBook G4 computer supports stereo sound output and input, available simultaneously. The sound circuitry handles audio data as 16-bit samples at a 48 kHz sample rate.
The sound circuitry and system software can create sounds digitally and either play the sounds through the built-in speakers or send the sound signals out through the sound output jack or one of the USB ports.
The PowerBook G4 computer can record sound data from either the built-in microphone, an audio CD, the audio input jack, or a USB audio device. For each sound input source, sound playthrough can be enabled or disabled. Sound data from digital sources is converted to analog form for output to the speakers and the sound output jack.