ED-229B provides the interoperability requirements (INTEROP) standard for the implementation of the Air Traffic Service (ATS) applications supporting the Baseline 2 data link services as specified in the Safety and Performance Requirements (SPR) Standard. Revision B takes into account results from SESAR and NextGen validation exercises, and maintaining portable data link services and applications independent, to the maximum extent practical, of the underlying network technology. Corrigendum 1 corrects purely editorial errors.