How do i find out my Xbox's device code?

Im trying to prioritise my xbox connection over my sisters computer by using Games and Application sharing - BT Home Hub on my pc. Its asking me to choose a game or application so i chose Xbox Live and it also wants me to choose a device. There are a lot to choose from and they all begin with "Unknown" followed by a load of numbers and letters, such as "Unknown-d8-a2-5e-bd-ff-e4". How do i find out which one belongs to my Xbox console.