The Kvaser USBcan Pro 4xCAN Silent is a ‘listen-only’ CAN interface. It is used by developers of highly sensitive autonomous or safety-critical systems to ensure that the interface has no impact on the bus or surrounding systems. It is also selected to prevent any application or third-party, such as a hacker, from impacting the CANbus and its related systems through the Kvaser device.

In contrast to a CAN interface with software-implemented silent mode, the Kvaser USBcan Pro 4xCAN Silent is internally wired by hardware to be permanently silent. This means it is not capable of transmitting any CAN data frames, error frames, or any other frames, and it will not participate in the normal CAN protocol by transmitting an Acknowledge (ACK) slot after receiving a proper frame from another device. More simply stated, in ISO 11898 terminology, the Kvaser USBcan Pro 4xCAN Silent interface will never drive the CAN bus to a dominant state.