I have 2 CS 50's ESI Linked together over a MPLS, at one of the locations I need to setup a remote phone. The customer doesn't want me to put the remote phone on there network so I am setting up internet for this on a different network. Can I have the ESI Link on the MPLS and the remote on the internet I am setting up. The MPLS is on the customers network.

If the remote phone (or any number of remote phones at different Internet locations) is physically separated on a different Internet connection, it should be able to connect to any cabinet that it's set up for and registered to. It shouldn't matter if there is ESI-Link in use.

The only way that this will work is if the router that is handling everything is able to handle 2 internet connections, and you can do the routing in that. Since you can not add an IVC card to the 50, and it only has 1 gateway in F822(which now points to the MPLS) that is your route out to the internet. Let us know if you get it figured out.