I have a question about initial contact with the tower at a controlled airport with multiple runway frequencies. I looked, but I didn’t find an answer in the AIM or the chart supplement for the airport I’m thinking of. The airport in question has two parallel runways. The large runway is used mostly used for large aircraft and business/commercial traffic. The smaller runway is used by GA aircraft and for training. Which frequency should I make initial contact with? Should I call on the frequency for the runway I intend to use? Should I call on the frequency of the large/main runway, and then request the other runway if that’s the one I want? Should I call on the frequency of the runway that’s closest to me from my direction of approach? (I’m coming in from the east, so use the frequency for the runway that’s farthest east on the airport.) Or is there some other standard way to choose? And what about airports with runways going all directions, like Boston for example?