This is a text string in the following form, based on Unix: 'Mmm _d yyyy hh:mm - Mmm _d yyyy hh:mm'. 'Mmm' are the first three letters of the month. '_d' is the day of month. A single-digit day is preceded by a space. 'yyyy' is a four-digit year. The range is from 2001 to 2100. 'hh:mm' is a 24-hour representation of hours and minutes. A single-digit hour or minute is preceded by a zero. An example is: 'Jul 1 2002 00:00 - Oct 1 2002 00:00'. When sysSummerTimeMode is date(3), the object can be modified. Empty string will be shown when sysSummerTimeMode is not date(3).