What is telemetry used for?

Hi.

This might be a dumb question :blush: for most of you but Iā€™m going to make it anyway.

What are the telemetry modules used for in a rover setup using the apm2.6 ?

You can make changes without having to plug a cable into the controller. Its a nice to have not a necessity

So, the telemetry set can only be used to send data to the APM2.6 ?