A single point in time can be represented by concatenating a complete date expression, the letter T as a delimiter, and a valid time expression. For example “2007-04-05T14:30”.If a time zone designator is required, it follows the combined date and time. For example “2007-04-05T14:30Z” or “2007-04-05T12:30-02:00”.Either basic or extended formats may be used, but both date and time must use the same format. The date expression may be calendar, week, or ordinal, and must use a complete representation. The time expression may use reduced accuracy. It is permitted to omit the ‘T’ character by mutual agreement.