Actually it is a USB input (since the data comes out of e.g. a Macbook and into the Topping).
In your case (when you want to use the coax-in on the BL5’s), you use it as a converter USB to (coax) S/PDIF….so yes, it has an outgoing coax.
I used it as a pure DAC – with the analog out into my Beomaster.
It is in general a very good device at a resonable price (please read the review in the link).
I do not have BL5’s here, but I would not hesitate to use the analog outs for the analog PL-in on the 5…….in fact I’d prefer connecting the Topping to an Aux-in on a Beomaster/sound/center and use the PL connection there for the 5’s.
Using the coax-in of the BL5’s can be a hassle because of the volume controlling (that has to be done with a B&O remote directly to the 5’s).
I do not, however want to start a discussion here about the pros and cons of using the digital-in on the 5’s!!!
My point is, if you want to use the digital-in of the 5’s for sound out of a Macbook, you’ll need a USB to coax converter….since the Macbook has no S/PDIF-out (unless yours would have the combo headphone/optical out).
MM