DIAL—for DIscovery And Launch—is a simple protocol that second-screen devices can use to discover and launch apps on first-screen devices. For example, your can stream a video from your embedded device on your connected TV.

1. Add COMPONENT_DEPENDS += DIAL to your application componenent.mk file.

2. Add these lines to your application:

   #include <Dial/Client.h>
   
   static UPnP::ControlPoint controlPoint;
   static Dial::Client* myClient;
   
   // Call when IP address has been obtained
   void onIp(IpAddress ip, IpAddress mask, IpAddress gateway)
   {
      // ...
   
      /* Use UPnP to auto-discover all DIAL-enabled servers */
      Dial::discover(controlPoint, [](Dial::Client& client) {
         // Are we looking for a specific device? Can match on friendlyName, UDN, etc.
         if(client.friendlyName() == F("FriendlyNameToFind")) {
            // Take a reference to the device
            myClient = &client;
   
            // Get an app and do something...
            auto& app = myClient->getApp("YouTube");
   
            // Keep this device
            return true;
         }
   
         // Don't want this device, destroy it
         return false;
      });
   
      // ...
   }

See the :sample:`DIAL_Client` sample application.

.. doxygennamespace:: Dial
   :members: