There is no set standard in law for Indiana.
Someday all 911 operators will have to be EMD certified, which is a 4 day course, but the state hasn't started enforcing that yet.
Most places, you get on the job training, to include EMD, IDACS, CAD, Radio, everything else.
If you want to become a dispatcher there are 2 things that you NEED, to be successful.
1) Know the area where you want to work. It makes training alot easier.
2) Be able to multi-task. It is a requirement, and no amount of training will teach you how.