It uses Ultranet protocol as the link in between boxes. There's a diagram in the doc showing analog input to the DN4816I, and then Ultranet output to a PD-16, but since the DN4816O can convert Ultranet to an analog output, it appears to be able to work standalone without a console. So the DN4816I is converting the analog signal to Ultranet, and the DN4816O is converting the Ultranet back to analog.
Thanks,Nate. The fog is lifting, if ever so slowly. If I am to understand this properly, use as a digital snake (DN4816I to a N4816O), would not need connection to Ultranet to work, as in a stand-alone digital snake?
As a DL16 has only 8 outputs, I can see the utility of a DN4816O to provide enough additional outputs to run additional IEM stereo mixes.