X-sampa is an extention to sampa that lets all International Phonetic Association's alphabet be used in Ascii-7, by defining, most notably, a few new diacritics (such as \, so that /3\/ is the rounded version of /3/). Lots of information on x-sampa and sampa can be found at http://www.phon.ucl.ac.uk/home/sampa/x-sampa.htm.