[78-L] abbreviations on a Columbia

[AllenAmet at aol.com]

Hi
 
  Can anyone assist on this question?
 
 "I just bought a tiny Columbia electric portable  that is like from the 
early '50s and where the needle carriage flips over  between 78 and 45/33, 
there are printed the letters "L" and "N".  I think  that the needle carriage 
is from Europe, it says made in Holland or  something "
 
  What do the letters L and N mean, back in  the 50s?
 
Allen