Notes:

1) Length is the value written into the length field of the message and is not necessarily equal to the number of bytes of data that are being transferred.

2) Data defines both the length of the data field and the ordering of bytes. The number of characters (hexadecimal digits or the - character) define the number of data bytes in the messages. The hexadecimal digit (modulo 4) shows the location of the data byte within the field. The leftmost character in the data field represents the one sent first.