As shown in Figure 1, the Extended CAN message is the same as the Standard message with the addition of:

Extended CAN: 29-Bit Identifier

• SRR—The substitute remote request (SRR) bit replaces the RTR bit in the standard message location as a placeholder in the extended format.
• IDE—A recessive bit in the identifier extension (IDE) indicates that there are more identifier bits to follow. The 18-bit extension follows IDE.
• r1—Following the RTR and r0 bits, an additional reserve bit has been included ahead of the DLC bit.