Library /sys$common/syshlp/patchhelp.hlb CHECK, NOT ECO, Parameters  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 eco-level
      Indicates the ECO levels that are not in use.  ECO levels can  be
      entered in:

           o  Comma-separated lists

           o  Colon-separated ranges

      Both comma-separated lists  and  colon-separated  ranges  can  be
      entered  on  the initial command.  However, only one ECO level or
      one range of ECO levels can be entered  in  response  to  an  ECO
      level prompt (ECO>).