# CAN Bus ## Protocal - SOF = Start of Frame - Arbitration ID - 11 bit on consumer vehicles, 29 bits on heavy vehicles, also the priority - Control Bits - RTR = Remote Transmission Request, requesting someone to respond - DLC, IDE... (6 bits in total) - Data - 64 bits - CRC = Cyclic Redundancy Checksum, 16 bits, to detect BER (Bit Error Rate) and self-correct - ACK: 2 bits - EOF = End of Frame - IFS = Inter-Frame Spacing - Differential signaling, two wires, CAN Low and CAN High, 120 ohm termination resistor - ODB-II (on-board diagnostics), which runs as a "higher layer protocol" on CAN bus