"alternate collating sequence" (acs) pages are pages that allow records to be sorted in a different order. collation is the assembly of written information into a standard order. in common usage, this is called alphabetisation, though collation is not limited to ordering letters of the alphabet. for instance, an acs might allow the sort order to sort in both case-sensitive and case-insensitive order. prior to version 6.0 only one acs was able to be stored in the file, however after 6.0 was released more than one acs page could be associated with a file at any one time.