When you say the 'light pipe install' do you mean the optical ports on the back of the 2480 or did you buy a
DIF-AT/
DIF-AT24 to go with your 2480?
The optical ports on the back of the unit are standard with the 2480's and handle SPDIF Digital (Stereo) signals only.
In order to utilize ADAT, you need a DIF-AT(24) box that connects to the 2480 via the RBus port.
They're getting pretty tough to locate these days, but DIF-AT's are still being sold on ebay for around $100-$150, but only work with 16 bit audio... The AT24's are even more scarce and can run up around $300 if you can find one, but handle 16/20/24 bit audio.
Hope this helps