There is absolutely no reason not to use a standard XLR if that is what you have just because its "digital". A digital signal is just 1's and 0's, no amplitude, no audio, doesn't need anything exotic. If it is an unbroken connection, the data travels and it always travels completely or not at all. There is no partial or degraded signal like an audio signal.
Having said that, there is nothing wrong with getting the specified cables if you can. Check out the link below for your cable needs. These guys are the absolute best I have found anywhere and their prices are competetive with anyone. They wil build pretty much anything you need to your specs.
They make Variax cables too.