Are file extensions, such as MP3, AIFF, BFM, XML, etc. abbreviations according to the Nemeth Code? Section 49.b states, “When a letter or sequence of letters does not represent a word or phrase, it must be considered as an abbreviation and must be transcribed according to the rules of this code.” It would seem to me that in some file extensions the letters do represent a word, but not in all. Specifically, I would like to know how to treat MP3, in the phrase “Jenny’s MP3 player cost $125.
A rule update dealing with unspaced number/letter or letter/number abbreviations has been posted on BANA's website. If an abbreviation consists of an unspaced combination of letters and numbers, the abbreviation is treated as a mathematical expression -- each letter individually capitalized, a dot 5 inserted before a number that follows a letter, and punctuated mathematically. This would not apply to such abbreviations as BFM which do not include any numbers. If those abbreviations appear in print preceded by a dot (or period) they would have to be brailled according to the Computer Braille Code.