I have a 2015 MBP (Thunderbolt 2), and I want to output to a new Thunderbolt 3 docking station. The new dock is connected to 2 monitors.

Seems like what I need is a male to male Thunderbolt2 to Thunderbolt3 cable. But, from googling around, doesn't seem like such a cable exists.

I see USB C to Mini DP male to male. But that's used for new laptops (USB C) to drive older displays (Mini DP).

I also see that Apple provides a Thunderbolt 3 to 2 dongle.


Thunderbolt 3 is male, Thunderbolt 2 is female. So I guess I could connect a Thunderbolt 2 cable from may MBP to the dongle. But even then, I'm not sure if that would work. Also, I'm not sure if it'd be driving 1 display or 2.

Can anyone help?


3 Answers 3


Get a proper Thunderbolt 2 dock.

The problem that you’re going to have is that Thunderbolt 2 does not provide all of the bandwidth and capabilities necessary to support what’s on the Thunderbolt 3 dock.

Using a USB-C dock with older MacBook Pros

Those Thunderbolt 2 to thunderbolt 3 adapters are great for when you’re using a single use items like an Ethernet port or a Firewire adapter. Thunderbolt 3 has double the bandwidth of Thunderbolt 2 - 40Gb/s versus 20Gb/s. You simply will not be able to support everything that the newer dock supports.

What’s also important to keep in mind is that the Thunderbolt 2 uses an active cable where as Thunderbolt 3 does not. So right off the bat trying to connect this dock to your older MacBook Pro will likely not work.


According to this Macworld.com article here you can use backwards compatibility by making sure that the dock you purchase is EXTERNALLY POWERED in order to supply access and power to the down-streamed device. Hope I helped!


A TB2/male to TB3/male cable can be easily constructed by pairing something like Apple's Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter with a Thunderbolt cable. There's almost certainly new products with the same capability available outside of Apple so consider those examples than any kind of endorsement. One limit of Apple's Thunderbolt adapter is it doesn't pass through DisplayPort video, and I'm unaware of any TB2-to-TB3 adapter that will do so.

One concern that I expect people to have is that there's no backward compatibility on TB2 ports for USB like with TB3. This was addressed in the TB3 spec in that any TB3 dock is required to have a USB controller to account for this very situation, if the TB3 dock doesn't fails to work because it is connected to a TB2 port then it is in violation of the spec.

One way to get USB 2.0 and 3.0 ports, Thunderbolt 3 (USB-C) ports, and video from a single TB2 port is to use an eGPU. In case the reader is unfamiliar with these devices an eGPU is an external graphics processing unit, it's a PCI GPU in a box typically used to assist in improved gaming and/or other graphics heavy applications with a laptop on one's desk while maintaining portability and battery life while the laptop is away from the desk. These are often more expensive than any Thunderbolt dock, and often lacking in ports seen on a Thunderbolt dock as the primary purpose is video performance, not as a general purpose docking station. It may be difficult to find an eGPU in stock at big box electronics stores but by knowing their name, "eGPU", they should be easy to find from those dealing in more specialty computer peripherals.

It's perhaps possible to get one TB2 port on an Apple computer to drive two displays but this is not supported by Apple. Using an eGPU is an exception because at that point it is the GPU in the box driving the displays, not the GPU in the computer. Apple doesn't support MST, multiple stream transport, which allows for daisy-chaining or splitting of a single DisplayPort signal to drive independent video displays. The best you will get is mirroring, the worst is no video on one display, the attempt to drive two displays from a single DisplayPort port will not damage anything. People that have installed Windows or Linux on Apple hardware found that the hardware supports MST but macOS does not, and there's all kinds of theories on why Apple does not support MST.

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