BIOS Printer Status Flags

 All INT 17H services return the printer port status as a set of bit flags
 in AH as follows:

 PrinterStatusRec
  ┌7┬6┬5┬4┬3┬2┬1┬0┐
  │ │ │ │ │ │0 0│ │
  └╥┴╥┴╥┴╥┴╥┴-┴-┴╥┘ bit  mask
   ║ ║ ║ ║ ║     ╚═► 0: 01H  1 = time-out error
   ║ ║ ║ ║ ╚═══════► 3: 08H  1 = I/O error
   ║ ║ ║ ╚═════════► 4: 10H  1 = selected (0 means off-line)
   ║ ║ ╚═══════════► 5: 20H  1 = out of paper
   ║ ╚═════════════► 6: 40H  1 = acknowledge (printer is attached)
   ╚═══════════════► 7: 80H  1 = not busy (note: 0 means busy)

See Also: Parallel Printer Adapter Ports
          INT 17H (BIOS printer support)
          BIOS Data Area
          ROM-BIOS Functions
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