Int 2F Fn 7F09  - Prindir V9.0 - Set Byte Counter Display                  [P]

   AX = 7F09h
   DH = new state (00h off, 01h on)

Return: AX = status
       0000h successful

See Also: AX=7F00h"PRINDIR",AX=7F07h"PRINDIR",AX=7F08h,AX=7F0Ah,AX=7F0Ch