Yes, it will work. I use the same Signalink and cable betwen my 817/857/950 with no problems.
Thanks, CMH! You may have noticed that I (D'ooooh!) thought to look at the Signalink website and saw that, about 5 minutes after I posted that question. :-/ Ol' Grampa Ken must have forgotten to take his brain medicine that morning. :-)
I've been too busy for a lot of activity, but I've worked a dozen or so contacts with the 950, and it's a BIG improvement over the 897 (same as the 857, I think.) That notch filter and adjustable-width filtering is GREAT on crowded bands. :-)
Thanks again, and 73!