There is no "key" as such. You have a subscription, which gives you a userid and password. With that you can update the memory cards which fit into the front of the panel via an adaptor which plugs into your PC's USB port. The cards will work in ANY unit, you can update ANYONE's card. You can only download one update per subscription - once it's done, that's it until the next month. If you can't use your subscription for any period of time then negotiate direct for an extension