Reading braille

Each braille cell has six dot positions in two columns of three, numbered 1 to 3 down the left and 4 to 6 down the right. Every letter is a different pattern of raised dots. The first ten letters, A to J, use only the top four positions. K to T add dot 3, and U to Z add dots 3 and 6, except W, which was added later.

Numbers reuse the letters A to J, marked with a number sign first: the number sign then A is 1. CacheCrack handles that for you. Geocaches sometimes use real braille plaques, bumps on a container, or dots painted on a surface.