It is possible to set the GPIO outputs according to the reception or transmission frequency. This is applicable for configurations with one or two orange PIs. This makes it possible to switch relays, for example, depending on the band worked.
To refer to the number of GPIOs and connection pins see the following articles :
For the Raspberry PI 4, in a terminal window type: pinout or go to the web page https://pinout.xyz
Since version 5, of Remote SDR, the configuration is done in the Settings page.