PURPOSE:
Check that external line out connection works correctly
STEPS:
1. Insert cable to speakers (with built-in amplifiers) on the line out port
2. Open system sound preferences, 'Output' tab, select 'Line-out' on the connector list. Click the Test button
3. On the system sound preferences, select 'Internal Audio' on the device list and click 'Test Speakers' to check left and right channel
VERIFICATION:
1. Do you hear a sound in the speakers? The internal speakers should *not* be muted automatically
2. Do you hear the sound coming out on the corresponding channel?
