Transmitting in different zones

Hi,
I wish to know how to choose between the three different zones when transmitting. I can’t find any information on this topic in the API documentation or anywhere else, maybe I’m looking at the wrong place.
Regards,
Robert
I wish to know how to choose between the three different zones when transmitting. I can’t find any information on this topic in the API documentation or anywhere else, maybe I’m looking at the wrong place.
Regards,
Robert