Setting credit and tariff

Posted by JD UK
What do the "Set credit" and "Set tariff" options, and all relevant data in the "Call costs" section of "Time & cost", do, and how can I use them to benefit myself?

Posted by BobaFett
it depends on your operator if its supported or not

This message was posted from a E60-1

Posted by JD UK
Okay, well what do they do if they are supported by the operator?