How do CAN signals operate when transmitting data?

In a Controller Area Network (CAN) system, data transmission relies on a differential signaling method that uses two wires, known as CAN High (CAN H) and CAN Low (CAN L). When transmitting data, CAN H toggles between a higher voltage (typically around 3.5 volts or higher) and CAN L goes to a correspondingly lower level (around 1.5 volts). This differential voltage allows for robust communication with noise immunity.

When a CAN bus is idle, both CAN H and CAN L are at approximately the same potential; when data is transmitted, one line goes higher (CAN H) and the other goes lower (CAN L). This change in voltage levels represents the binary values being transmitted, and the difference in voltage levels between CAN H and CAN L is what encodes the data. This is why the option stating that CAN H toggles up to 3.5 volts accurately describes the operation of CAN signals during data transmission.