7556 and it's 6 versions newer and should work, you will likely need to update existing ports from 139 to 445 to make it work.
7970, don't load the one on Xerox.com, run the one I linked.
The 7556 needs to be upgraded the old school method (USB or dumped onto it via CWIS)
7970 is updated via tool installer (run the file from a PC, needs JAVA)