The recently updated ISO 11898-2:2024 standard specifies CAN HS (high-speed) transceivers as well as CAN FD (flexible data rate) transceivers as in the ISO 11898-2:2016 standard. In general, there is no difference in these standards regarding these transceiver types. An exception is the definition for the dynamic symmetry parameters. Now, these parameters are guaranteed for the complete bit-rate range, which is specified in the transceiver product datasheet. For example, a lot of so-called 5-Mbit/s CAN FD transceivers are used at 2 Mbit/s. The intention behind, that the so-called 5-Mbit/s transceiver behaves at 2 Mbit/s as specified at 5 Mbit/s, is not covered in the ISO 11898-2:2016 standard. This modification will be explained in the updated CiA 601-1 technical report about CAN FD node and system design recommendations (revision is in preparation and comes soon).

Additionally, ISO 11898-2:2024 specifies the CAN SIC (signal improvement capability) transceiver, originally described in the CiA 601-4 specification (document has been withdrawn after releasing the ISO standard), and CAN SIC XL (extended data-field length) transceivers, deriving from the CiA 610-3 specification (has been withdrawn, too).

In order to avoid confusions, the following terms should be used to typify CAN transceivers:

• CAN HS: legacy transceiver supporting bit rates up to 1 Mbit/s, with or without lower-power mode and/or selective wake-up capability.
• CAN FD: legacy transceiver supporting bit rates of 2 Mbit/s and more (e.g., when using a point-to-point topology), with or without lower-power mode and/or selective wake-up capability (only when qualified for 5 Mbit/s and using CAN CC wake-up frames).
• CAN SIC: new transceiver providing signal improvement capability and supporting bit rates up to 8 Mbit/s, with or without lower-power mode and/or selective wake-up capability (using CAN CC wake-up frames).
• CAN SIC XL: new transceiver providing signal improvement capability and the FAST mode with error signaling disabled (up to 20 Mbit/s), with or without lower-power mode (selective wake-up capability is not possible).

There are also other CAN transceiver types specified in other documents, such as CAN LS (low-speed) transceivers with fault-tolerant functionality and low-power capability supporting bit rates up to 125 kbit/s (ISO 11898-3). There is an additional fault-tolerant transceiver standardized in ISO 11992-1 supporting a bit rate of 125 kbit/s for point-to-point links; it is used for connecting towing and towed heavy-duty road vehicles. The SWC (single-wire CAN) transceiver specified in the SAE J2411 document supports a nominal bit rate of 33,3 kbit/s. It is not recommended for new designs.

Within the CiA organization, we have two activities related to cybersecurity. The IG (interest group) 04 SIG (special interest group) 01 CAN XL develops a data link layer (DLL, OSI layer 2) cybersecurity add-on function for CAN XL. It is intended that this approach can be implemented in hardware. Additionally, on July 24 CiA is going to inaugurate the IG06 SIG02 HLP (higher-layer protocol) cybersecurity. The aim of this SIG is the specification of security add-on functionality for OSI layers above the data link layer i.e. for OSI layer 3 (network layer) to OSI layer 7 (application layer) for CAN based networks, in particular for CAN CC and CAN FD based protocols that will not directly profit from the CAN XL security add-on functionality. CiA is calling for cybersecurity experts to work within this SIG. Interested parties may contact secretary(at)can-cia.org.

The CiA Technical Committee (TC) task force (TF) Modeling accompanies these cybersecurity-related specifications to model them as specified in ISO 7489-2 and related standards.

There is also a need to discuss the political dimension of cybersecurity measures for different applications. Which measures are necessary? It might be that in some applications a mechanical access protection is sufficient, e.g. for deeply embedded networks. In other applications, an end-to-end protection might be appropriate. If an attacker has access to the CAN network lines, OSI layer cybersecurity add-on functions might be required. As such, CiA is currently considering to establish a Marketing Group (MG) to discuss and to develop design guidelines and recommendations for applying technical cybersecurity measures for different use cases.