0c499685_HP_94D_E_F__Other_Registers
[Command] OPEN [AH Register] 0Fh [Other Registers] 
AL= Channel number to open ES= Segment of file or handler name BX= Offset of file or handler name DS= Segment of parameter area* DX= Offset of parameter area* * (built-in serial port handler only)
HP-94D/E/F
Other Registers