Offset  HexVal  DecVal  Type    Note
00      F0      240     7b      SOX
01      43      67      7b      Yamaha Manufacturer ID
02      0000nnnn        nibble  Device ID
03      7A      122     7b      Message ID
04      0bbbbbbb        7b      Message length LSB
04      0bbbbbbb        7b      Message length MSB
