Site to Site REST Calls in Provider Hosted Solution

I need to read from/insert into a list that resides on one site collection from a page that lives on a different site collection.  I have tried CSOM and it's not working I think because this is a provider hosted solution.  Is it possible to use CSOM (javascript) to do this?  If not can I use REST and what if any special configuration/authentication is required.  Thanks in advance for help!