In Bluetooth world, how well known GUIDs convert into Device UUID's

Question

I am researching on Bluetooth development in Xamarin.

At connection state, all the c# code connects via a well known ID that defines a Bluetooth profile.

Well, in the demo examples I see code

UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");    // ("fa87c0d0-afac-11de-8a39-0800200c9a66");

What is "00001101-0000-1000-8000-00805F9B34FB"? Is it being somehow obtained from fa87c0d0-afac-11de-8a39-0800200c9a66?

Even more, in the Bluetooth documentation, we see the well known UUID's for different profiles in a form:

HandsfreeAudioGateway   0x111F  Hands-free Profile (HFP)

How would 0x111F be converted into a 00001101-0000-1000-8000-00805F9B34FB form correctly?

I suppose people with Bluetooth development experience would be able to comment and clarify these points.

Answer 1

It's just that the 16 bit versions are always added to the 128 bit Bluetooth Base UUID of:

00000000-0000-1000-8000-00805F9B34FB

The 1101 then inserted makes the uuid refer to the Serial Port Profile making it:

00001101-0000-1000-8000-00805F9B34FB

111F just refers to the Hands Free Profile. The full 128 bit version would be:

0000111F-0000-1000-8000-00805F9B34FB

I don't see how that other UUID you listed would be referring to the Hands Free Profile without passing through some masking layer though.