High Quality Content by WIKIPEDIA articles! Crisis Response Operations in NATO Operating Systems (CRONOS) is a system of interconnected computer networks used by NATO to transmit classified information. It provides NATO Secret level operations, with access to NATO intelligence applications and databases. As of 1999, a wide area network of NT computers used in NATO in Europe. CRONOS provides e-mail, the Microsoft Office Suite, etc. It provides informal messaging (e-mail) and information sharing within the NATO community. There is no connectivity between CRONOS and any US network or with the coalition wide area network.