How do I check the Digital Link USB is detected on a Mac?

Click on the Apple menu () in the top right corner of your screen.

apple menu

Now click on the 'About this Mac Option'

about

Click on the System Report Button,

and then click Hardware > USB on the left hand panel.

panel

If you have the Digital Link Interface cable connected, and your Mac has found the cable it should show up under USB devices.

panel highlight

The Digital Link Interface Cable will show up as TTL-232R-3V3-AJ or TTL-232R-5V-AJ. If it is showing, then all should be working correctly.