How to call a function between angular components?

First of all let's talk about the implementation, I'm using Angular in its version 1.6, and I'm starting to implement the use of the components. I am creating a single page aplication and I am using components to divide the tasks. I also use auto-executable functions of javascript to build the controllers.

I have the problem when I need to call a function in the component controller from the main controller. I know that bindings can be used to send parameters, but I do not know how to trigger a nested function from the main controller, since it is not aware of the functions of the component's controller.

Component configuration:

(function(angular,AppName){     
    var app = angular.module(AppName); 
    app.component("informacionInicialComponent", {   
        controller : "informacionInicialController",
        bindings:{
            ordenServicio : "=",
            abrirStep : "="
        },
        templateUrl : "./rel/views/templates/informacion_inicial.html",  
    });

}(window.angular, window.AppName));

I know that the objects sent by the bindings can be called from the component controller using this for this I implement a variable $scope.x = this in the following way:

(function(angular, AppName){
    var app = angular.module(AppName); 
    var controller = function($scope){

        $scope.indexController = this;
        

        $scope.funcionAllamar = function(){
            console.log("ejecutando funcion desde controlador principal");
        }
    };

    controller.$inject = ["$scope"];
    app.controller("informacionInicialController", controller);

}(window.angular, window.AppName));

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.0/angular.min.js"></script>

I want to call the function in this case called funcionALlamar from the main controller, but I do not know how to do it, and I heard something about using triggers but I do not know how to implement them, I would appreciate any help what can you give me?