High-speed CAN is the "classic" CAN bus (according to ISO11898-2), used in many (industrial) applications. The bit rates, defined by the "CAN in Automation" user organization are ranging from 10 kbit/s up to 1 Mbit/s. CAN signals are transmitted differentially. Using high-speed CAN, the differential voltage for dominant bits is 2 V, for recessive bits 0 V.

A: The dominant level of the CAN-high wire is 3.5 V.
B: The recessive level of CAN-high and CAN-low wires is 2.5 V.
C: The dominant level of the CAN-low wire is 1.5 V.
Low-Speed CAN, or Fault-Tolerant CAN, is designed for improved durability. The recessive level of the differential signal is at -5 V, the dominant level is 2.2 V. If one of the two data lines is damaged, there is an automatic switchover to single-wire mode. This allows the system to be operated. The bit rates ranging from 40-125 kbit/s.

A: The dominant level of the CAN high wire is 3.6 V.
B: The recessive level of the CAN high wire is 0 V, of the CAN low wire 5 V.
C: The dominant level of the CAN low wire is 1.4 V.