On that subject

["grant finlay" grantfinlay]

John,
According to Sound Devices on the spec's page for the 702, all you
need to do is to attach a BNC to RCA plug on the end of your cable,
that way you can use the SD702 as your A/D going into the s/pdif
input of your sound card.
As I mentioned before, it's very important to make sure it's a
"digital cable @ 75ohms"
Here's one I found via a quick search:
http://www.monstercable.com/productdisplay.asp?pin=3D2352
(Use a gold plated bnc/rca on the end, in theory it has less resistance)

And from the SD site;
http://www.sounddevices.com/products/702.htm

SD702:
I/O =96 Digital:
AES3-id 75 ohm, 0.5 V p-p, S/PDIF compatible with RCA adapter

Hope that helps and saves you a few bucks..
Have a XXXX on me!

Regards,
Grant Finlay.
http://naturesounds.co.nz