From FrathWiki

Conlang Extended X-SAMPA

The collective modification of X-SAMPA which is preferred on the Conlang mailing list. It includes some alternative codings for greater clarity, notably & for [æ], &\ for [ɶ], i\ for [ɨ], and u\ for [ʉ].

A thorough description and automatic CXS<->Unicode IPA converter can be found at http://www.theiling.de/ipa/