Are you sure? I've never seen a "casette SIO cable". I've only seen SIO cables. All being the same. I suppose the ones that are wired in (on the 410, XM301, etc) might not carry through all signals, but then those go at the end of the chain anyway. Have you checked continuity? You may just have a broken cable...
--Kurt
Yes I whipped out my multimeter and the cable is good just not the right lines used. for example pin 7, 10 not used