I heard that Telcordia has replaced Bellcore, why?

That's true, Bellcore no longer exists and has been replaced by Telcordia.  This happened back in 1997.  At that time, Bellcore was acquired by SAIC, one of the world's leading providers of systems integration, information management, data security and network solutions.

Bellcore was formed in 1984 as a direct result of the AT&T Divestiture.  AT&T's Central Services Organization became Bell Communications Research, Inc.  Initial duties included:

Telcordia is the keeper of the NEBS Criteria and continues to maintain these standards.

For more historical information, click here.