1. Biometrics - This is basically required for printing EAD cards and GC plastic cards. INS officers take digital photographs, digital signature of the applicant, finger print of the right index finger,
2. Regular FP is basically used by FBI to perform name check, criminal records check etc. INS officers take finger prints of all 10 fingers.
After reading few threads and other member's responses, my understanding is like this. You can see one of the following code in your FP notice and it means as follows:
Code 1 -> Regular Finger print
Code 2 -> Biometrics
Code 3 -> Both regular Finger Print and Biometrics