Communication between classes

[Cronnoc]

I am creating a game using modular programming (I can replace any part of the code without affecting another part).

Here is how i have it structured
The Game class has instances of Network, Graphics, Input, and Audio classes.
Each of those classes have instances of their respective modules.

I need a way to allow a module of Input to connect to a module of Network. My current system involves the Input module sending a signal up to Game and then Game sends a signal down to Network. The problem is, I don't know how to have the module send a signal back to Game. I can easily send the signal down to Network. So if anyone could show me how to do that it would be very much appreciated. Also if you have another way for me to do this, I am open to restructuring my program, then please tell me.

[mutexe]

what do you mean by "signal"?
Can't you pass a Game reference down into the instances it contains so you always have a back reference?

I can replace any part of the code without affecting another part

So presumably you've implemented Network, Graphics, Input, and Audio classes as interface-type classes?

[Cronnoc]

Nevermind I found a solution. I am implementing an Event system into my game.