An OpenSky radio must log in and be validated by the controller. Once it logs in, only then does it download its profile of talk groups which is based on a 10 digit radio ID.
Once you turn on the radio it only takes a couple seconds before you're up and running. Our were set to log in automatically but they can also be set to require a password.
The radio is useless until it successfully logs in.
OpenSky is likely to go away eventually.