Sound Inputs

The Power Macintosh G3 computer provides a stereo sound input jack on the back of the enclosure for connecting an external PlainTalk microphone or other sound source. The sound input jack accepts a standard 3.5-mm stereophonic phone plug (two signals plus ground).

Note

The Apple PlainTalk microphone requires power from the main computer, which it obtains by way of an extra-long, 4-conductor plug that makes contact with a 5-volt pin inside the sound input jack.

The sound input jack has the following electrical characteristics:

input impedance: 20 k
maximum input level without distortion: 2.5 V peak to peak (Vpp) maximum
line-level microphone voltage range of 0.28 V to 2.1 V peak to peak
input SNR <90 dB unweighted (typical) for recording to system hard disk drive or main memory