How to Pass Data from TELEM2 to TELEM1

Can anyone tell me how to pass Mavlink data packets from TELEM2 (which is a Raspberry Pi) to TELEM1 (which is a 915MHz 3DR Radio)?

I am trying to pass data (0-255) from an app running on the Raspberry Pi to another app ruining on the ground control computer.

Thanks in advance for your assistance.


You might start here:

So you have a Raspberry Pi on Telem2 which needs to send some data to a ground station that’s attached to Telem1. If you send the data to APM it’s not going to know what to do with it and through it away.
You could build a new Mavlink packet and make the APM send it back out as a Mavlink packet but you would need to modify the APM code to do that.