Depending if you enabled Secure services or not, if your at a remote location, all you need to do is to type in the url address to the WAN IP address and the port number that is listed in the Remote access feature:
http://191.205.117.50:#### port number after (
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If you enabled Secure Server then do the following:
https://191.205.117.50:#### port number after (
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Port number will change if you enabled secure server.
Port number will be listed in the remote management web page.
Not sure if that WAN IP address is a private or public IP address, maybe private. If so, this still wont work until you get a public IP address on the 850L routers WAN side...##.##.###.###