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Physical layer

2nd edition of ISO 11992-1 released

The physical layer standard for the truck-trailer communication has been updated. Now, it complies with that what is used in European commercial vehicles since many years.

The European Regulation No 13 describes the truck-trailer communication for braking and running gear (Photo: Stock Adobe)

Regulation No 13 of the European Commission specifies the communication interface between truck and trailers: “The electric control line shall conform to ISO 11992‑1 and ISO 11992‑2:2003 and be a point-to-point type using the seven-pin connector according to ISO 7638‑1 or ISO 7638‑2:1997.” The transceivers used in the vehicles for years were not completely compliant with ISO 11992‑1. The second edition of ISO 11992‑1 has fixed this. Now, the standard has been adapted to the implemented transceivers. Unfortunately, the most used IC (integrated circuit) implementation is not publically available. One of the market-leading provider of ISO 11992 devices, Wabco, offers its transceiver chip also to its main competitor Knorr-Bremse, so that this implementation is widely used. Other companies provide discrete circuitry implementations complying with the 2nd edition of ISO 11992‑1.

The recently published edition of ISO 11992‑1 is written with requirement statements, which can be referenced easily in conformance tests plans. Several requirements have been updated to comply with the on the market available implementations. In the informative annex implementation examples for the bus failure management are given. Basic specifications such as the bit-rate and bit-timing are the same as in the first edition.


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