My MB Air (early 2015) has a Thunderbolt 2 port. I need an adapter to USB-C for a USB hub. TB2 is so outdated that search results for such an adapter only reference mini display or USB-B. Are these all the same? I know Apple sells a TB2 to USB-C adapter but it’s $50, sigh. Help! … I’ve fallen into the black hole of cable terminology hell and I can’t get up. (My first attempt to pull myself up was Glen’s great article about cables …but it only references TB3+).
Thanks!
How about…
Those connectors/cables are not all the same.
What is your goal here? Sounds like XY problem. You’re focused on the cable but the problem is connecting the MBA to a USB hub.
Why not buy a compatible USB hub? That would be one with USB-A connector (the old classic) at USB 2.0 or 3.0 speed. Almost unlimited choice as they’re very common.
I would second what @gingerbeardman wrote.
Although physically USB-C and modern TB (TB3/4) use the same connector, the protocols are not interchangeable. Add older TB1/2 don’t even speak USB natively.
Your older TB2 port speaks TB only (which is actually PCIe plus DP mode), but not USB. So what an actual (and, yes, usually expensive) adapter does is bridge from PCIe (which your TB2 does speak) to USB, which is what your hub exclusively speaks. That bridge circuitry is what makes such an adapter more expensive than just a dongle that accommodates different physical ports. This is a $73 example, but it ends in USB-A not C so best case an appropriate additional cable/adapter would still be required.
Note also, I believe the $50 Apple adapter you mention is actually not such a bridge. It adapts physically from TB2 to TB3, but it does not actually bridge TB2’s PCIe protocol to USB protocol.
Confusion about this tends to arise because TB switched physical connectors from mDP to USB-C when it went from version 2 to 3. Also, TB3 can speak native USB (in addition to PCIe and DP) so if your Mac had TB3 (or 4 for that matter), you could just connect it straight to your hub and be done.
But that’s just the boring background. Following what @gingerbeardman suggested, I’d say you need to see if you can get a hub that you can directly attach to one of your USB-A ports (there are tons of inexpensive USB hubs out there, even such that go from A to C, like this $10 example), or perhaps, you instead opt for a TB2 hub (like the example above, but there must be inexpensive used units out there too) that would allow you to go straight from your TB2 to whatever USB devices you’d like to attach (including additional USB hubs for yet more USB devices). I had such TB1 and TB2 docks back in the day for attaching all kinds of USB devices and monitors to older TB1/2 MBPs. They were expensive at the time (like $300), but a well kept used unit should run you near nothing nowadays I would assume. I threw mine out long ago so I’m afraid I can’t help with that.
Thanks, Simon. In your usual fashion, you explained the nuts and bolts (or ins and outs) so that I understand the options, not just what the options are.
I’m trying to reduce clutter, and with only 2 USB ports, was hoping to take advantage of the TB2, for several external data drives, not for charging or startup. But not worth big bucks. I like your $10 solution, and will probably go that route, especially considering the age of the Air.
Thank you for the kind words. 
Your idea to reduce clutter makes perfect sense. Only problem is doing that over TB2 is likely not cost effective compared to going the USB hub route.
The one nice advantage you can exploit is that you can daisy chain USB devices including hubs. So even if you have only two on-board ports, you can add as many hubs as you need to attach all your devices (just keep in mind max ~500 MB/s for all of them together). And you don’t need to sacrifice a Mac port for the hub if you plug whatever was there before into one of the hub’s d/s ports.
One last suggestion — if you have many devices, especially disks, you’ll want to make sure you get a powered hub (especially in your case since USB-A per its older standard doesn’t need to deliver as much power as USB-C’s guaranteed 15 W on every Mac). A tad more expensive, but you’ll thank yourself later. Intermittent connectivity issues with peripherals are a huge pain to troubleshoot, so better to just stay way clear of that potential trap. 
More good points. I hadn’t’ thought about daisy chaining hubs, not just devices, and power issues with drives. I’m in process of replacing several large bulky hard drives, attached separately to the Air and a 2017 iMac, with SSDs. The Air sits in front of the iMac, iMac keyboard sits on top of closed Air when in use. Tight quarters! So a couple hubs, with little SSDs will be huge improvement — even if desktop clutter remains 
. Thanks again.
My Mac mini (2018) and its predecessor (a 2011 mini) uses a 10-port USB-C hub for most of its devices:
Anker USB A Hub, USB 3.0 Hub, 10 Ports USB Hub for Laptop & PC…
It works very well, but (as a large powered hub) is not a portable device that you’d want to throw into a laptop bag. But it would be great to leave on a desk for quickly connecting/disconnecting peripherals.
High-capacity USB hubs (anything with more than 7 ports and in some cases, those with more than 4 ports) actually implement a device-tree using a two or more internal hubs. Daisy-chaining hubs is no better or worse than a large hub, but a single large hub means you only have to deal with a single power adapter.
Ten ports is more than I need, so am going with this for the Air —
Amazon.com: Atolla 4-Port USB 3.0 Hub with 4 Data Ports, 1 Smart Charging Port, Individual On/Off Switches and 5V/3A Adapter : Electronics —
And this for the iMac (and any future Mac) —
https://www.amazon.com/dp/B0D9Q9WCLX?ref=ppx_yo2ov_dt_b_fed_asin_title
Thanks again for details about how everything works…
I’m only paying for that if it includes ADB and SCSI 