 When two or more systems have agreed on how to interpret the information in such a request, they can achieve semantic interoperability "for that specific type of transaction".For semantic interoperability generally, it is necessary to provide standardized ways to describe the meanings of many more things than just commercial transactions, and the number of concepts whose representation needs to be agreed upon are at a minimum several thousand.How to achieve semantic interoperability for more than a few restricted scenarios is currently a matter of research and discussion.