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What is the correct cable for a iMac desktop Thunderbolt/usb4 port to an external HDD usb 3.0 for the late 2015 27" iMac 7,1?

I have a late model 2015 iMac, 27", model 7,1. My System report says this iMac has 4 usb 3.0 bus ports and 2 Thunderbolt/usb4 ports. I have an external Seagate Desktop 8TB External Hard Drive HDD – USB 3.0 for PC, Laptop And Mac, arriving today. I'd like to connect it to one of the Thunderbolt/usb4 ports. Can someone please advise me on the proper connector to do this? I see usb, usb 3, 3.1, A, B, C, Thunderbolt 3, Thunderbolt 4, etc.. (I do recognize HDMI ports/connectors) but there are too many others to fathom. Could someone please advise on the proper connector to use for the iMac desktop Thunderbolt/usb4 port to the Seagate usb 3.0 external HDD .


Thanks.


Posted on Dec 5, 2021 8:06 AM

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15 replies

Dec 5, 2021 4:37 PM in response to rkaufmann87

The External Hard drive arrived, is set up, and now has a bootable backup. The USB hub also arrived and is working. The External Hard Disk is connected to the Hub, mounted to the desktop, and available. I restarted from the new backup and it works fine when connected directly to the iMac or to the External HD. The charging station on the Hub also works.


All that said, I'd still prefer to connect the External HD to the Thunderbolt port. I have two Thunderbolt ports and I'm not using either of them.


So, I have included a photo of the cable end that connects directly to the External HD. I don't know what type of connector this is. Right now, the other end is the standard USB 3.0 that connects to the HUB, but I want a cable that connects the External HD to the Thunderbolt 2. Is there one that will allow me to do that? If so, I'll order it as soon as I know what type it is.


Thanks, again, for any help you can give me.

Dec 5, 2021 8:33 AM in response to Dedo

The Late-2015 27-inch iMac has two Thunderbolt 2 ports and four USB-3.0 ports. There are no USB4 ports on it.


If your Seagate drive came with a USB-A cable, just plug it into any available USB-3 port on the iMac. As long as it is rated USB-3.0 - 3.2 Gen1 or Gen2, it will be backward compatible with the USB-3 port on the iMac.


If the cable that came with the Seagate is the smaller USB-C cable, then you will need either a USB-C to USB-A male 3.0 or later cable or a USB-C female to USB-A male 3.0 or later dongle.

Dec 5, 2021 10:31 AM in response to rkaufmann87

Thank you for the quick reply. Hopefully, I have ordered the right thing. Coming with the external HDD is a Powered USB Hub, atolla 4-Port USB 3.0 Hub with 4 USB 3.0 Data Ports and 1 USB Smart Charging Port, USB Splitter with Individual On/Off Switches and 5V/3A Power Adapter.


Should that just be connected to the iMac or can I, via a proper cable, connect that to the Thunderbolt port?


Dec 5, 2021 10:41 AM in response to rkaufmann87

Thank you for the quick reply. When on click on the Apple System Report, it names those two ports Thunderbird/USB4. When I open that link, the title is Thunderbolt Bus. That's part of why it's confusing to me. When I search the web, I find all sorts of different references and types, some of which are compatible, some not.


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Sorry, wrong reply to you. This was meant for VikingOS but apparently unable to delete it here.


Dec 5, 2021 10:38 AM in response to VikingOSX

Thank you for the quick reply. When on click on the Apple System Report, it names those two ports Thunderbird/USB4. When I open that link, the title is Thunderbolt Bus. That's part of why it's confusing to me. When I search the web, I find all sorts of different references and types, some of which are compatible, some not.

Dec 5, 2021 11:57 AM in response to VikingOSX

For the 'Tapered Edge' late 2015 Aluminum iMac, it says four USB 3.0 ports, dual Thunderbolt 2 ports. So, given that (it still puzzles me the machine would say something other).


Can I use my Thunderbolt 2 port to directly connect my external USB 3.0 external HDD? Would it be faster for data transfer? And, if so, what cable do I need to do that? If not then it will be iMac USB 3.0 to Seagate HDD USB 3.0.

Dec 5, 2021 11:58 AM in response to rkaufmann87

Different people have different thoughts. I would like to hear your opinion, please.


For the 'Tapered Edge' late 2015 Aluminum iMac, it says four USB 3.0 ports, dual Thunderbolt 2 ports. So, given that (it still puzzles me the machine would say something other).


Can I use my Thunderbolt 2 port to directly connect my external USB 3.0 external HDD? Would it be faster for data transfer? And, if so, what cable do I need to do that? If not then it will be iMac USB 3.0 to Seagate HDD USB 3.0.

What is the correct cable for a iMac desktop Thunderbolt/usb4 port to an external HDD usb 3.0 for the late 2015 27" iMac 7,1?

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