| Pin | 
    Name | 
    Description | 
  
  
    | 1 | 
    Ground | 
     | 
  
  
    | 2 | 
    Ground | 
     | 
  
  
    | 3 | 
    Ground | 
     | 
  
  
    | 4 | 
    Ground | 
     | 
  
  
    | 5 | 
    -12V | 
    -12 VDC | 
  
  
    | 6 | 
    +5V | 
    +5 VDC | 
  
  
    | 7 | 
    +12V | 
    +12 VDC | 
  
  
    | 8 | 
    +12V | 
    +12 VDC | 
  
  
    | 9 | 
    ? | 
    ? | 
  
  
    | 10 | 
    PWM | 
    Regulates speed of the drive | 
  
  
    | 11 | 
    PH0 | 
    Control line to send commands to the drive | 
  
  
    | 12 | 
    PH1 | 
    Control line to send commands to the drive | 
  
  
    | 13 | 
    PH2 | 
    Control line to send commands to the drive | 
  
  
    | 14 | 
    PH3 | 
    Control line to send commands to the drive | 
  
  
    | 15 | 
    WrReq- | 
    Turns on the ability to write data to the drive | 
  
  
    | 16 | 
    HdSel | 
    Control line to send commands to the drive | 
  
  
    | 17 | 
    Enbl2- | 
    Enables the Rd line (else Rd is tri-stated) | 
  
  
    | 18 | 
    Rd | 
    Data actually read from the drive | 
  
  
    | 19 | 
    Wr | 
    Data actually written to the drive |