IEC 61158-4-3:2010 describes the protocol that provides communication opportunities to a pre-selected "master" subset of data-link entities in a cyclic asynchronous manner, sequentially to each of those data-link entities. Other data-link entities communicate only as permitted and delegated by those master data-link entities. For a given master, its communications with other data-link entities can be cyclic, or acyclic with prioritized access, or a combination of the two. This protocol provides a means of sharing the available communication resources in a fair manner. There are provisions for time synchronization and for isochronous operation. This second edition cancels and replaces the first edition published in 2007 and constitutes a technical revision. The main changes with respect to the previous edition are:
- Corrections in Table A.15 and Table A.16;
- Expired patent removed and added new patents. This bilingual version (2012-07) corresponds to the monolingual English version, published in 2010-08.