Indicate the key type with "t=x" where x is A, D, N, or I.
"A" indicates an ASCII sort. The keys will be compared using the ASCII collating sequence (i.e., "A" is less than "a" and "B" is less than "a").
"I" indicates an International sort. The keys will be compared using Apple's International Utilities package (i.e. "A" is equal to "a" and "a" is less than "B"). This is the default if you do not indicate the key type.