An example Angular channel service. It abstracts the event dispatch/subscribe to make it easier to implement/use. Here are some pub/sub best practices: http://eburley.github.io/2013/01/31/angularjs-watch-pub-sub-best-practices.html.

authentication_channel.js

/**
 * AuthenticationChannel
 * 
 * Usage (from within a controller):
 AuthenticationChannel.onSetPin($scope, function(pin){
    console.log("Pin set to ", pin);
 })

 //anywhere else in your code base
 AuthenticationChannel.setPin(1234567); //set the pin
 */
define(
    [],
    function() {
        var AuthenticationChannel = function($rootScope) {

            var setPin = function(pin) {
                $rootScope.$broadcast("pinSet", pin);
            };

            var onSetPin = function($scope, handler) {
                $scope.$on("pinSet", function(event, pin){
                    if(hander && typeof handler === "function")
                        handler(pin);
                });
            };

            return {
                setPin: setPin,
                onSetPin: onSetPin
            };

        };

        AuthenticationChannel.$inject = ['$rootScope'];

        return AuthenticationChannel;
    }
);