With federal inmate texting, messages are relayed via the federal Corrlinks/TRULINCS technique

https://prisontexting692.meridiannest.com/posts/how-to-pick-the-best-federal-inmate-text-app-for-secure-communication-2

With federal inmate texting, messages are relayed because of the federal Corrlinks/TRULINCS machine, and replies can go back to the out of doors user as original text messages.