The Carbon is a multi-format technical camera, designed to use digital backs and film backs, with copal shutter-ed lenses. The camera was a effectively an ALPA 12 TC clone (and propably a pretty lousy one at that), which I could only dream of affording at as a 19 year old.
The digital back I had was an old Mamiya one, I had gotten it after my intership at Hassleblad, where it was given to me as a parting gift by one of the senior employees there. I believe it was a trade-in they had laying around.