The sound system accepts inputs from five possible sources:
The microphone preamp has a dedicated analog input channel in the Snapper ciruitry; the other inputs send digital data. The analog input can be set for play-through or recording. The digital inputs can be selected or mixed by the Snapper sound circuitry.
The computer also accepts digital sound data from the DVD-ROM/CD-RW Combo drive or from devices connected to the USB or FireWire ports. Sound data from those sources can be sent to the sound system to be converted to analog form for output to the speakers and the output jack.
The built-in microphone is located at the bottom of the left speaker grille.
The sound signal from the built-in microphone goes through a dedicated preamplifier that raises its nominal 30-mV level to a nominal 150 mV (peak-to-peak) signal to the sound circuitry. That signal level assures good quality digitizing without driving the analog input into clipping.
The audio input jack is a 3.5-mm mini phone jack located on the I/O panel on the back of the computer. The audio input jack accepts line-level stereo signals. It also accepts a stereo miniplug-to-RCA cable adapter for connecting stereo equipment to the computer.
The sound input jack signal connections are:
Modem activity sound signals from the communications slot are sent to the Snapper sound circuitry as 8-bit digital data.