after some more looking, it _is_ mentioned in 4.2 as well. It also seems
to be driven by the same dc driver as the regular builtin serial hardware
on a KN02 or similar box. Makes sense, as that was more or less standing
on its own two feet, unlike the ioasic machines of later day. 
I shouldnt have opened my mouth wihtout poking deeper in the source!
But from what  now see, there isnt any distinction between the dc thats
built in and this device. 

now to try to find one of these for myself :)

isildur