I have read that, but that certainly did not work for me.
Reset to factory defaults. Plug it in. Connect router.
There is zero configuration required.
These came locked down with no ability to change settings so they HAD to be pre configured.
If after resetting it you have no sync then it's broken.
If after resetting it you have sync but no internet then the issue is with your router.
I'm happy to try again, but I have yet to see the DSL light lit, with any settings. Would you expect this to be lit even before the router has been connected?
Yes. It should sync.