Source : Free On-Line Dictionary of Computing

X.400
     
         The set of {ITU-T} communications standards
        covering {electronic mail} services provided by data networks.
        X.400 was widely used in Europe and Canada.
     
        X.400 addresses tend to be much longer than {RFC 822} ones.
        They consist of a set of bindings for country (c),
        {administrative domain} (a), {primary management domain} (p),
        surname (s), given name (g).
     
        For example, the X.400 address,
     
        	c=gb;a=attmail;p=Universal Export;s=Bond;g=James;
     
        might be equivalent to RFC 822
     
        	[email protected]
     
        [Reference?]
     
        (2003-06-24)