Hi Mike - been awhile.
I spoke to Mike last Friday (he doesn't have th e980 yet). I wanted to replace my 700 with a second 850 (I guess you can see where my head is at).
There are some simple solutions to the serial thing.
First, a serial card for the PC is dirt cheap and easy to install.
Second, there are USB > Serial Adapters that are available (and a bunch that don't work very well). I asked Mike what adapters are bullet proof and he gave two places to look . First, the Belkin F5U109, second - Keyspan products.
I don't know anything about the monoprice cable shown above.
Hope it helps.