I just bought a new MacBook Pro with Thunderbolt 3 ports built in, and I have an old 12inch MacBook with a USB-C port. I was trying to use target disk mode with migration assistant to transfer data from my 12inch Macbook to my new MacBook Pro. I searched online and saw somewhere people say that Thunderbolt 3 cable can be used to do the job, moreover, there is information stating a Thunderbolt 3 can be used as USB-C cable as well, so I ordered Belkin Thunderbolt 3 cable on Amazon.(https://www.amazon.com/Belkin-USB-IF-Certified-Thunderbolt-Compatible/dp/B0725DW6D3/ref=sr_1_4?ie=UTF8&qid=1511766135&sr=8-4&keywords=belkin%2Bthunderbolt%2B3&th=1).
I received the cable today. However, by directly connecting my new MacBook Pro and MacBook 12inch, the new MacBook Pro couldn’t recognize that 12inch MacBook. I did some more research later, and on this page(https://support.apple.com/en-us/HT201462 scroll down to the bottom), it seems that a USB-C 3.1 cable is the only way that does the work.
I am quite confused since couldn't a thunderbolt3 cable be used as a USB-C 3.1 cable? Or, Apple just made it that way that the USB-C port on 12inch MacBook cannot recognize a Thunderbolt 3 cable? After this experience, I really want to understand the differences between USB-C and Thunderbolt3. By watching a lot of youtube videos explaining those differences, it brought to me even more questions, which are what I am asking here...
So almost all the videos explaining Thunderbolt 3 and USB-C include USB A and USB B as well, and there is 1.0, 2.0, 3.0...version numbers too. Based on what I saw and my understanding, seems like the A, B, C types and those version numbers evolve separately.
Does USB type letter A, B and C refer to shape only? Because all type A(no matter it is 1.0, 2.0 or 3.0) are the usual shapes of USB port we see and type B are those unusual shapes of ports we see, and type C is the one we see with PixelBook and other latest devices.
Does version numbers refer to speed only?
What's the relationship between USBC and Thunderbolt 3? Does Thunderbolt 3 fall into the category of USBC or, Thunderbolt 3 just "borrows" a USBC shape and in the meanwhile, it is a superset of USB 3.1 as well?
Somebody says USB-C is USB 3.1. Is it correct? Since if a letter only refers to shape and number refers to speed, then there shouldn't be an equivalent.
Please advise... Thanks guys!