Hi everybody :blush: I have bought a Numato Lab 16ch USB relay Link: Numato 16ch USB relay The setup should be fairly simple, but I seem to be missing something, so I hope you can help me :see_no_evil: Link to relay connections: relay connections First the basics: The relay is connected to Ras…

And can you manually write a value to the device, say “relay on 0”? Often times it’s a matter of sending the correct terminating character on the end. Have you tried adding chr(10) or chr(13) (or both)?