Edward Peterson70 said:I need to hook up a new MacBook Air—it’s got two USB-C ports—to an older iMac. If I remember right, the iMac video input only takes Thunderbolt. The goal is to use the iMac as a monitor for the Air.
USB-C hubs usually have an HDMI output, but then I'd just need another HDMI to DP or Thunderbolt adapter. That feels messy, and there's a good chance it won't even work.
What's the best way to do this?
All MacBooks use Thunderbolt, especially the newer ones. Remember, Thunderbolt is a transfer standard, not just a physical plug.
Newer MacBooks have USB-C ports that support Thunderbolt, which carries the DisplayPort signal. Older models have MiniDP connectors that carry that same DisplayPort signal.
So, theoretically, if you grab a passive adapter (or a dock) with a USB-C male to MiniDP female connector, and then run a MiniDP-miniDP cable to the target iMac, it should work.
Or just get a single cable that's USB-C on one end and MiniDP on the other.
Personally, I just use a USB-C to full-size DisplayPort cable. Works flawlessly whether I'm using a Thunderbolt dock or just plugging directly into a laptop's USB-C port that supports DP.
Bottom line: forget about HDMI. Don't even bring it into the conversation. Trying to go through HDMI will likely just kill your DisplayPort compatibility.
Anyway, MiniDP and DP should be 100% compatible (both ways), so if you pick up an adapter like this for the iMac, you could use a standard DP cable to link the iMac to a dock with a DP output, or just use a USB-C to DP cable straight to the MacBook.
So these two items might solve the problem (but don't quote me on that 😁) https://www.amazon.com/example-link-1 https://www.bestbuy.com/example-link-2
