Donn\'ees endoscopiques d'un groupe r\'eductif connexe: applications d'une construction de Langlands

Let $F$ be a global field, and $G$ a connected reductive group defined over $F$. We prove that two endoscopic data of $G$ which are equivalent almost everywhere, are equivalent. The result remains true for (non-twisted) endoscopy with character. We also give, for $F$ global or local and $G$ quasi-simple simply connected, a description of the elliptic endoscopic data of $G$.