When you activate the comparison mode and open a timetable, it will be opened twice, once with a green frame, i.e. current data, and once with a red frame, i.e. data you want to compare.
You can customise some settings in order to help you find out the differences of the two sets of data much faster.
Only modified timetables
This option selects only those timetables which hold differences. The selection list and any printout options will only show these timetables.
Room changes are often not so dramatic for the people involved as shifting a period. Therefore, you can define here that only the changed timetables should be shown excluding the timetables in which only rooms have been changed.
Detailed comparisons for couplings
If you select this option then periods are marked as changed where only a different coupling line was changed and not the current coupling line.