Consider this NOTAM for LAX from the current list:
FDC 5/0341 LAX IAP LOS ANGELES INTL LOS ANGELES CA. ILS OR LOC RWY 25L AMDT 12C... S-ILS 25L DA 395/ HAT 291 ALL CATS VISIBILITY ALL CATS RVR 2200. ADD NOTE FOR INOPERATIVE ALSF-2 INCREASE S-ILS 25L VISIBILITY ALL CATS TO RVR 4500. EXCEPT WHEN ADVISED BY ATC THAT EQUIPMENT IS DOWN. CONSTRUCTION EQUIPMENT 178 MSL BEGINNING 1399 FEET NORTHEAST OF RWY 25L. 1502052152-1508042152EST
What does S-ILS25L
signify, how is it different than just ILS25L
, and where can I find the source document?