0c499685_HP_94D_E_F__Other_Registers
[Command] BUFFER_STATUS [AH Register] 06h [Other Registers] 
AL=00h Flush key buffer AL=01h Get # of Bytes in key buffer AL=02h Flush recv buffer for built-in serial port handler AL=03h Get # of bytes in recv buffer for built-in serial port handler
HP-94D/E/F
Other Registers