Does it work without signal?

DeskOps needs a connection to read or write your numbers; it does not keep an offline copy of your books on the phone. When the connection drops, the app says so with a calm banner rather than spinning, and tells you when it is back. Anything you were typing stays on the screen until you can send it. Money numbers refresh on their own when you return to the app after a while, so a page you left open in the truck is not stale when you look at it again.