Int 14 Fn 400E  - I1541 - Get Info                                         [t]

   AX = 400Eh

Return: AX = LPT port I/O address in use (0000h if no cable in use)
   BL = LPT number (1..3) in use (00h if no cable in use)
   CF set if the cable is auto-detectable
   CF clear if cable could not be auto-detected or is not present

See Also: AX=4000h