The first one I used was not a very good experience. We went to the store and purchased a parallel port zip drive. We opened the documentation and read the instructions how to set up the parallel port zip drive. We spent too much time on trying to make it work. Then I noticed the little dial on the back with numbers 5-6 on it.
Turns out they had boxed a scsi zip drive in a parallel port box. Since they were both 25pin everything connected just fine.