North
South
East
West
E.G
The alpha characters "N", "E", "W", and "S" indicate positions within the Northern or Southern hemisphere for latitude, and the western or eastern hemisphere for longitude:
"N" = north latitude / west longitude
"E" = north latitude / east longitude
"W"= south latitude / west longitude
"S" = south latitude / east longitude
You could google ARINC 424 for FMS lat/long data entry.