· The start of frame bit marks the beginning of the data frame, it consists of a single dominant bit.
· The Arbitration Field consisting of 12 bits: The 11-bit Identifier, which reflects the contents and priority of the message, and the Remote Transmission Request bit. The Remote transmission request bit is used to distinguish a Data Frame (RTR = dominant) from a Remote Frame (RTR = recessive).
· The next field is the Control Field, consisting of 6 bits. The first bit of this field is called the IDE bit (Identifier Extension) and is at dominant state to specify that the frame is a Standard data Frame not an interframe space. The following bit is reserved and defined as a dominant bit. The remaining 4 bits of the Control Field are the Data Length Code (DLC) and specify the number of bytes of data contained in the message (0 - 8 bytes).
· Data field: The data being sent follows in the Data Field which is of the length defined by the DLC above (0, 8, 16, ...., 56 or 64 bits).
· The Cyclic Redundancy Field (CRC field) follows and is used to detect possible transmission errors. The CRC Field consists of a 15 bit CRC sequence, completed by the recessive CRC Delimiter bit.