1. Run an optical cable from your G5 to a 192

2. Set your audio output to digital on your g5 (this is in “system preferences|sounds”)

3. Change an input on your 192 to optical

4. Make an aux with the optical input as it’s source, and output set to your normal monitor path.

5. Check the sample rate of your G5.  Do this by going into the “Audio MIDI Setup Utility”  Make sure the sample rate is set toe the same sample rate you are working at.

6. Check it by playing something on your G5 (iTunes or Quicktime etc.)

Now at this point you should hear audio, but you will get clicks and pops because the g5 is not synced to anything, it’s just running off it’s own internal clock.  There are 2 ways you can fix this.

1. You can sync your Pro Tools rig to your G5, which works if you don’t have any other digital audio peripherals that you interface with. Do this by opening the session setup window (command + 2 on the number pad) and select the optical Input as your Clock Source.

OR…
You can sync your G5 to your PT rig. (I prefer this method)

1. connect an optical cable from the 192 out to the G5 in. Your G5 will automatically sync to your 192!(see note below)

2. Breathe a sigh of relief that you never have to worry about CoreAudio or Re-Wire ever again!

NOTE: An Additional step is necessary when running osx 10.4 or older… osx 10.5 and newer automatically uses the optical in as a sync source if it is connected.) If you are running OSx 10.4; while Pro Tools is running, Open up “Audio MIDI Setup” (in osX utilities) and choose “external” for clock source.

The only drawback of this method is that you have to sync your G5 every time you start Pro Tools if you are using osx 10.4 or older.  When PT is closed the G5 reverts back to internal clock.