Batboard

For building a DSTAR Relais I need to switch the Packet speed of my Motorola Radius GM300, Modell M34GMC29C3AA, from 1200 baud to 9600 baud. Unfortunately I can't find any information how to do this and hope to find help how to solve this problem here in this forum.

Best, OE3FPA

Your GM300 does not have any "switch for Packet speed".

You need an external interface and that requires a service monitor to do the set up and get the modulation correct.