Pin 1: Ground Pin 18: Direction
Pin 2: *Change Pin 19: Ground
Pin 3: Unused Pin 20: *Step
Pin 4: *In Use 1 Pin 21: Ground
Pin 5: Ground Pin 22: *DKWD
Pin 6: *In Use 0 Pin 23: Ground
Pin 7: Ground Pin 24: DKWE (Write Enable?)
Pin 8: *Index Pin 25: Ground
Pin 9: Ground Pin 26: *TRKD
Pin 10: *Select 0 Pin 27: Ground
Pin 11: Ground Pin 28: *Write Protect
Pin 12: *Select 1 Pin 29: Ground
Pin 13: Ground Pin 30: *DKRD
Pin 14: Unused Pin 31: Ground
Pin 15: Ground Pin 32: *Side
Pin 16: *MTRI Pin 33: Ground
Pin 17: Ground Pin 34: *Ready
Note: some 3.5-inch drives may use different pins for the *Change (diskchange) signal.