This is a peripheral. USB OTG doesn't apply, and USB-A would be "inappropriate". Pretend this is an inkjet printer. What plug would you expect to find on that?
On Tue, 14 Feb 2017, Chris Elmquist wrote:
A Centronics-style 36-pin Amphenol. oh, sorry. <crawls back under rock>
("blue-ribbon")
A DB25 Howzbout a DE-9? Original style USB-B