OTD500 is antenna + router in a single box. There is nothing else needed. I just put it outdoors with a POE cable. Originally, I used it as a backup, but now I have an unlimited SIM, so I use it as a second internet connection.

If you mean the standard routers (like the Rutx50), Teltonika itself sells external enclosures with antennas. https://www.teltonika-networks.com/products/accessories/ante...