Inside the elevator inside the number of buttons "1" below a letter "B", what does that mean? Question added: "B" is optional? More
Each elevator in the meaning of B may be different, such as some B1, B2 ... ... that the ground floor, the second floor of the ground ... ...; some 1B, 2B ... ... that the first floor half, second floor half ... .... So the specific meaning depends on the specific situation.
No meaning, just a code, if you like it, with A B C D .... can be similar to some people in the 4 layer do not want to use 4 to directly represent, with 3A, 13A, 23A and other subtitles Instead, of course, you like the words with 3X, 13X, 23X ... ... can be.
Should be negative layer! See how people arrange, parking, shops. Upstairs is a few A to a few, generally downstairs on a layer of B1B2 slightly
Is the next layer of 1, generally refers to the frame because the layer of -1 said the basement, so casually choose a letter hunger and nail as a fixed layer
