2215- part numbers are not the cable part number, they are 2457- part numbers. I think for the one you want it is 2457-24701-003. The pin outs for that are in the RealPresence Group series Integrator's Reference Guide, page 77 in the one I have open looking at it.
To get pricing and to order items like this you would need to contact a Polycom reseller, generally whomever you purchased your product from in the first place. This is an old cable and the item may not be available, CDW or whomever will have to check on it.
Places like CDW resell Polycom products and can take care of small items like this.