1.Lauch ProTools
2.Goto to "Setups" and choose "Playback Engine" and press "Yes"
3. Click on "OtherOptions"
4. Set Optical format to "ADAT"
5.MAke sure S/PDIF Mirroring is off
6.Make sure S/PDIF Compatability is set to "Other" , unless you are using a first edition Tascam DA30.
7.Hit the "Done" button .
8.Now change your clock source to "S/PDIF"  and then the "OK" Button.
9.Select S/PDIF-L and S/PDIF-R for the input of your Audio Tracks.
Press the REC Button on the track and you will see the S/PDIF Input registering!
10.Thats it!