Carbon was originally created in 1999 and was overhauled a decade later. Alternate letters such as the unicase T of the original are still available as OpenType stylistic alternates. Some of the numerals and most of the punctuation has been redesigned. Accents cover more languages. Along with new weights and italics, there’s Carbon Fence with a 1960s style choppy wire fence effect. Carbon includes fractions & numeric ordinals. Don't forget to read the files inside the zip for details.
These fonts are a free part of a larger font family which you can see here: http://j.mp/ahNVhL