I will be happy to review the configurations for you. Unfortunately, I cannot provide any advice on the Linksys device, but the ADTRAN units should be setup with static routes (as mentioned previously) to get the routing to work properly. The video Configuring T1 Access will provide additional information about this application.
Please, let me know when you have the configurations, or if you have any questions.
I went ahead and flagged the "Correct Answer" on this post to make it more visible and help other members of the community find solutions more easily. If you don't feel like the answer I marked was correct, feel free to come back to this post to unmark it and select another in its place with the applicable buttons. If you have any additional information on this that others may benefit from, please come back to this post to provide an update. If you still need assistance, we would be more than happy to continue working with you on this - just let us know in a reply.