> For the complete documentation index, see [llms.txt](https://agopengps.gitbook.io/agopengps/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://agopengps.gitbook.io/agopengps/frequently-asked-questions/frequently-asked-questions/teensy-4.1/swapping-gps-ports.md).

# Swapping GPS ports

If you connected your Teensy up over USB and are monitoring its output, you might see this message - "Swapping GPS ports".

This indicates that for whatever reason, the Teensy and your U-blox modules are unable to communicate. Check the connections on the board are good, and that the F9Ps are well settled in the sockets.