Permit F (provisionally admitted foreigners)An F permit is issued to persons who have been expelled from Switzerland but whose expulsion has proven to be inadmissible (violation of international law), unreasonable (due to concrete danger to the person) or impossible (for technical reasons). The permit is valid for 12 months and can be extended by the canton of residence for 12 months at a time. The cantonal authorities may grant a permit for gainful employment to temporarily admitted persons.
Identity card N (asylum seekers)An N permit is issued to persons who have applied for asylum in Switzerland and are in the asylum procedure. During the asylum procedure they basically have a right of presence in Switzerland. Under certain circumstances, they may be allowed to engage in gainful employment.
Identity card S (persons in need of protection)This permit entitles the holder to stay temporarily in Switzerland, but neither to cross the border nor to return to Switzerland. If persons with an S permit take up a job or change jobs, they must obtain a permit for this purpose. They must present this permit to the competent cantonal authority two weeks before the expiry date without being asked to do so. A change of address must be reported to the competent authority within eight days. This pass is not proof of the holder's identity.
Recognized refugees either receive asylum and thus a residence permit (B permit) or they are provisionally admitted as a recognized refugee and receive an F permit (provisionally admitted refugee). Recognized refugees with a B permit as well as with an F permit can stay and work in Switzerland permanently.
For more information on these residence permits, please contact here or also here.
You can get an overview of the residence categories in the asylum area here.