Presentation of CCSD and the services which are offered : CCSD is an approach to open archives : international vocation, "researchers" trend, concern for long-term archiving. Full-text databases of scientific articles and theses, bibliographic databases. Presentations of CSSD services : - Hal server with its vocation of articles server, its connection as first submission bone towards ArXiv. MetHal extension for bibliographic references - TEL server, with its vocation of theses server. - the searching mirror for ArXiv, the mirror of Physnet The collaborations of CCSD with Cornell, MathDoc, CERN, INIST,... Submission rules into CCSD server and supported documents formats Export protocols and the technologies which are used. The textual version of this presentation at the Conference "Open Access to Scientific and Technical Information: State of the Art and Future Trends" was published with the title 'The Centre for Direct Scientific Communication' in "Information Services and Use" vol. 23 (2003), issue 2-3, p. 133-137.