the way I take it, is that the left dial has numbers 6-9 on the top and bottom. Top 6-9 for positive shift transmitters, and lower 6-9 for negative shift transmitters. Then the right dial has has 0-9 for the second number of the freq. So i take it as you have a positive shift transmitter (ex: Hitec), so that gives you the first number as bing 6-9 which is 4 numbers and the second number as 0-9 which is ten, that would give you a total of 40 combinations.

Am I taking this the right way or are there not frquencies of 91-99. if not then that would make 30