Captain Sim released the 777 Captain II for Prepar3D a few weeks back, and more recently released the -300 expansion pack. To make life easier for PC pilots, Captain Sim has now released their Wireless CDU for the product.
By downloading and connecting the Wireless CDU app to your mobile device (iOS or Android), you can then connect it to your simulator aircraft to control it from your mobile device. The app itself is free to download from your preferred app store, but the connection module will cost you $14.99. Once downloaded and installed, you will be able to control everything from route input, V-Speed calculations and more.
You are required to own the 777-200 Captain II base pack from Captain Sim before being able to download and install.