Also known as: ITU-T Recommendations

The main products of ITU-T are Recommendations (ITU-T Recs) - standards defining how telecommunication networks operate and interwork. There are over 4000 Recommendations in force on topics from service definition to network architecture and security, from broadband DSL to Gbit/s optical transmission systems, next-generation networks (NGN) and IP-related issues.

http://www.itu.int/en/ITU-T/publications/Pages/recs.aspx