Two computers and one Studio Display?

[Keroro1]

If I'm reading this correctly, you used the switch + included cables and were able to get it working with M1 and at 5k.

Glad to see another data point

Yes with M1 mac mini, but with the MBP i7 don't.
I think it is related to how the cable (or the switch) has to deliver power and transfer data at the same time.
This MBP its really hot, needs lot of power to work.

 

[edanuff]

@edanuff

What's the downside of DSC?

Are these the cables that worked for you?

Cable Matters [USB-IF Certified] 10 Gbps Gen 2 USB C to USB C Cable 3.3 ft / 1m with 8K Video and 100W Power Delivery in Black

Cable Matters [USB-IF Certified] 10 Gbps Gen 2 USB C to USB C Cable 3.3 ft / 1m with 8K Video and 100W Power Delivery in Black

www.amazon.com

Hard to say what the downside is of DSC, supposedly not visually noticeable under normal conditions but didn't want to take the chance.

Yes, that's the cable that worked for me.

 

[joevt]

- The CableDeconn USB-C Switch only can handle up to 10Gb/s cables (incompatible with Thunderbolt 4)

When using the switch, does the Studio Display not appear as a Thunderbolt device connected at 20 Gbps in the Thunderbolt tab of System Information.app?

 

[Sir Ruben]

I'm purchasing from Amazon.co.uk. The English in the ad is so poor that I can't tell if it comes with 2 USB-C cables or not. Anyway its arriving today so we'll see in a couple of hours.

 

[trevor-b]

I'm purchasing from Amazon.co.uk. The English in the ad is so poor that I can't tell if it comes with 2 USB-C cables or not. Anyway its arriving today so we'll see in a couple of hours.

Yes, it wasn't clear from the description. But we have confirmation that there are 2 cables.

 

[Sir Ruben]

UPDATE: Okay it arrived today. I can confirm that mine also came with the recommended USB-C cables included and it also worked very well. Its very small and seems to stay completely cool during use. I had the adapter plugged into the Studio Display and I had my Mac Studio and work Dell laptop connected to the adapter. The select button quickly switched between them, and when I selected my laptop input it would also charge the laptop with no issues. Teams calls etc were able to use the Studio Displays camera and sound with no problems also.

On the Mac Studio side of things the Mac still recognised the display correctly with the same default resolution and appeared to be business as usual, although I did encounter the occasional (rare) flicker. Its worth noting that I powered the adapter with one of the USB-A ports on the back of the Mac and this seemed to work fine. I did not try connecting it to the mains via a power brick.

My home office has an L shaped desk so I usually have my Mac Studio and Studio display facing me, and when I turn to the right I have my work laptop and a 21" Dell monitor there. This has always worked ok and I can quickly switch back and forth between work and personal. Im my use case it ended up being the preferred option so I am not going to keep the adapter.

Overall though I do recommend it and I thank the original poster as it will help a lot of people. If you have just the Studio Display, or you have limited desk space this is a brilliant solution and the only one I am aware of so far.

 

[edanuff]

UPDATE: Okay it arrived today. I can confirm that mine also came with the recommended USB-C cables included and it also worked very well. Its very small and seems to stay completely cool during use. I had the adapter plugged into the Studio Display and I had my Mac Studio and work Dell laptop connected to the adapter. The select button quickly switched between them, and when I selected my laptop input it would also charge the laptop with no issues. Teams calls etc were able to use the Studio Displays camera and sound with no problems also.

In System Information, does the Studio Display show up under the Thunderbolt tab or not? Some users of this switch have seen the Studio Display still showing up as a Thunderbolt device in System Information and others (myself included) have not. Curious to see what yours is showing.

 

[Sir Ruben]

In System Information, does the Studio Display show up under the Thunderbolt tab or not? Some users of this switch have seen the Studio Display still showing up as a Thunderbolt device in System Information and others (myself included) have not. Curious to see what yours is showing.

Not sure about that sorry and its all packaged up now so I can't check.

 

[edanuff]

Not sure about that sorry and its all packaged up now so I can't check.

No worries, I'm going to give using one of these a second try since it looks like the magnetic couplers just don't last very long (daily usage to switch between a Mac and PC and one of the two couplers already had to be replaced). I'll report back what I find once it gets delivered.

 

[jacklivehere]

one of my magnetic connector already spoiled (after 4th day)
Today I switched to YIWENTEC USB-C USB3.1 Type-C 8K Switch which is bit cheaper than earlier post. And it's working fine with my Mac Studio and MacBook. USB ports on ASD also switch to Mac Studio or MacBook based on where its connected which is a plus.

ASD shows up as Thunderbolt device using this switch but as 20g connection rather than 40g earlier.

 

[Johnf1285]

For the users that have these Amazon USB-C switches, do you camera, microphone, and speakers continue to work as expected without any issues? I am thinking of going this route once I get my desk set up finalized. Swapping cables with the magnetic connectors is nice, but not quite nice as pushing a button. I personally don't need the extra bandwidth on the ports on the Studio Display itself, so that's a non issue for me personally. But the camera, microphone, and speakers are a must.

 

[edanuff]

Just received the "updated" CableDeconn switch.

Cables that worked at 5K@60Hz:

• Included cables
• Belkin Charge and Sync Cable to Windows PC
• Cable Matters USB C to USB C Monitor Cable 6 ft.
• Cable Matters Active USB C Cable 10 ft (but as Alt-Mode DP, not TB)

Cables that did not work:

• Apple Thunderbolt 4 Pro Cable (3 m)
• Apple Thunderbolt cable (1 m)
• [Intel Certified] Cable Matters 40Gbps Active Thunderbolt 4 Cable 6.6 ft
• Elfesoul USB C to USB C Cable, 3.2 Gen 2 USB-C Cable 6.6ft
• Huawei VR 2 Computer Connection Cable To Windows PC
• Fasgear USB C to USB C Cable 10ft USB 3.1 Gen2
• LEIRUI USB C to USB C 3.2, 9.9FT
• TREBLEET 10ft (3m) USB4 Cable

Very hard to say why certain cables work and others don't. Something to do with how the cable's e-marker chip identifies itself causes the Mac to not shift to a video signal that the switch can handle. Not sure why the Cable Matters USB C Monitor Cable works whereas the Elfesoul cable that seems to indicate the same specs does not. No idea why the Belkin VR Cable works and the Huawei VR Cable does not.

When it works, the display is showing up as Thunderbolt 3 20 Gb/s (except with the Cable Matters unidirectional Active Cable) which didn't happen when I tried one of these switches a few months ago (presumably a previous revision):

 

[TheBigApple2006]

Just received the "updated" CableDeconn switch.

Cables that worked:

• Included cables
• Belkin Charge and Sync Cable to Windows PC
• Cable Matters USB C to USB C Monitor Cable 6 ft.

Cables that did not work:

• Apple Thunderbolt 4 Pro Cable (3 m)
• Apple Thunderbolt cable (1 m)
• [Intel Certified] Cable Matters 40Gbps Active Thunderbolt 4 Cable 6.6 ft
• Elfesoul USB C to USB C Cable, 3.2 Gen 2 USB-C Cable 6.6ft
• Huawei VR 2 Computer Connection Cable To Windows PC

Very hard to say why certain cables work and others don't. Something to do with how the cable's e-marker chip identifies itself causes the Mac to not shift to a video signal that the switch can handle. Not sure why the Cable Matters USB C Monitor Cable works whereas the Elfesoul cable that seems to indicate the same specs does not. No idea why the Belkin VR Cable works and the Huawei VR Cable does not.

When it works, the display is showing up as Thunderbolt 20 Gb/s which didn't happen when I tried one of these switches a few months ago (presumably a previous revision):

View attachment 2025342

Thanks for this - Does it actually go to 60Hz on 5K native resolution?

 

[joevt]

Thanks for this - Does it actually go to 60Hz on 5K native resolution?

20 Gbps Thunderbolt or USB/DispalyPort 10Gbps is sufficient for 5K or 6K 60Hz when DSC is supported which I believe is the case for Apple's 5K and 6K displays.

 

[edanuff]

20 Gbps Thunderbolt or USB/DispalyPort 10Gbps is sufficient for 5K or 6K 60Hz when DSC is supported which I believe is the case for Apple's 5K and 6K displays.

TLDR: For 5K/6K video purposes, it works as either a Thunderbolt 2.0 20Gbps switch or as a DisplayPort 1.2 20Gbps/USB 2.0 480 Mbps switch. With DSC (display stream compression), you can do 5K@60hz. Ignore the 10Gbps spec in the marketing, that’s for USB devices such as ssd drives and you’ll never see anything close to that performance if you’re using this with a 4K+ display.

—-

I think the marketing of these things is confusing but I am reasonably sure these things are not limiting the DisplayPort bandwidth to 10gbps and that that is referring to the maximum USB data bandwidth available in USB 3.1 Gen 2 for users who are using this device to switch data devices. My expectation is that when used for monitors that this is working exactly the way that USB-C does for Alt Mode DisplayPort 1.2 and that at 4K+ resolutions it is using up to 20 Gbps for the video stream and then per spec that this thing is only passing the USB 2.0 480Mbps data lanes through for device usage. It’s basically a DP 1.2 switch that can also do up to USB 3.1 gen 2. Now what’s interesting is that this revised model is able to sustain a Thunderbolt handshake between the Mac and the ASD which means that the Mac TB controller can do a smarter interleave of video and data so that you can probably get better data rates to the hub ports on the back of the ASD than you would if it was running pure Alt Mode DisplayPort.

 

[joevt]

TLDR: For 5K/6K video purposes, it works as either a Thunderbolt 2.0 20Gbps switch or as a DisplayPort 1.2 20Gbps/USB 2.0 480 Mbps switch. With DSC (display stream compression), you can do 5K@60hz. Ignore the 10Gbps spec in the marketing, that’s for USB devices such as ssd drives and you’ll never see anything close to that performance if you’re using this with a 4K+ display.

—-

I think the marketing of these things is confusing but I am reasonably sure these things are not limiting the DisplayPort bandwidth to 10gbps and that that is referring to the maximum USB data bandwidth available in USB 3.1 Gen 2 for users who are using this device to switch data devices. My expectation is that when used for monitors that this is working exactly the way that USB-C does for Alt Mode DisplayPort 1.2 and that at 4K+ resolutions it is using up to 20 Gbps for the video stream and then per spec that this thing is only passing the USB 2.0 480Mbps data lanes through for device usage. It’s basically a DP 1.2 switch that can also do up to USB 3.1 gen 2. Now what’s interesting is that this revised model is able to sustain a Thunderbolt handshake between the Mac and the ASD which means that the Mac TB controller can do a smarter interleave of video and data so that you can probably get better data rates to the hub ports on the back of the ASD than you would if it was running pure Alt Mode DisplayPort.

Right. A USB cable has one HighSpeed line (480 Mb/s) and 4 separate SuperSpeed+ lines, each capable of up to 10 Gbps. USB 3.x uses two of the lines for USB 3.x transmit and receive (5 or 10 Gbps in each direction), leaving two lines for DisplayPort. If four lines are used for DisplayPort (HBR3 is 8.1 Gbps per line = 32.4 Gbps total on the wire = 25.92 Gbps of DisplayPort data) then only the HighSpeed line (480 Mb/s) can be used for USB.

Thunderbolt uses all 4 SuperSpeed+ lines at 10 Gbps each, two for transmit and two for receive for 20 Gbps total in each direction. Thunderbolt tunnels PCIe and DisplayPort through the same Thunderbolt connection. PCIe is used to communicate with a USB controller in the display. Any bandwidth not used by DisplayPort can be used by PCIe.
5K60 (936MHz) @ 12bpp = 11.23 Gbps. ≈8 Gbps for USB.
6K60 (1286MHz) @ 12bpp = 15.432 Gbps. ≈4 Gbps for USB.

Usually, a passive USB-C 10 Gbps cable can connect Thunderbolt at 20 Gbps. I'm not sure why a connection through a switch would cause a USB connection instead of allowing a Thunderbolt connection.

A Thunderbolt 3/4 cable capable of 40 Gbps can transmit 20 Gbps per line.

 

[edanuff]

Right. A USB cable has one HighSpeed line (480 Mb/s) and 4 separate SuperSpeed+ lines, each capable of up to 10 Gbps. USB 3.x uses two of the lines for USB 3.x transmit and receive (5 or 10 Gbps in each direction), leaving two lines for DisplayPort. If four lines are used for DisplayPort (HBR3 is 8.1 Gbps per line = 32.4 Gbps total on the wire = 25.92 Gbps of DisplayPort data) then only the HighSpeed line (480 Mb/s) can be used for USB.

Thunderbolt uses all 4 SuperSpeed+ lines at 10 Gbps each, two for transmit and two for receive for 20 Gbps total in each direction. Thunderbolt tunnels PCIe and DisplayPort through the same Thunderbolt connection. PCIe is used to communicate with a USB controller in the display. Any bandwidth not used by DisplayPort can be used by PCIe.
5K60 (936MHz) @ 12bpp = 11.23 Gbps. ≈8 Gbps for USB.
6K60 (1286MHz) @ 12bpp = 15.432 Gbps. ≈4 Gbps for USB.

Usually, a passive USB-C 10 Gbps cable can connect Thunderbolt at 20 Gbps. I'm not sure why a connection through a switch would cause a USB connection instead of allowing a Thunderbolt connection.

A Thunderbolt 3/4 cable capable of 40 Gbps can transmit 20 Gbps per line.

Yes, this is correct per the spec. What I'm saying is that I believe that this switch is a very simple device with a high speed mux chip in it that probably can only handle 5.4 Gbps per lane (for a total of 21 Gbps). I don't think it's at all aware of any of the protocols being sent over it, it just switches the lanes and lines between two USB-C inputs and the output. Someone should do a teardown but it won't be me . Anyway, with that in mind, I suspect that the reason that it works with some cables and not others has to do with the cable and what the e-marker chip inside the cable tells the host computer it is capable of. These USB 3 Gen 2 cables that work with it must advertise to the computer a rate that keeps the signal within the tolerance of the switch (whether they're sending 10Gps USB data or Alt-Mode 20Gbps HBR2 DisplayPort). Better cables that tell the computer that they can handle a faster rate are probably causing it to fail. What's interesting is that the Mac Thunderbolt controller appears to be able to switch into a non-standard "slow TB3" of 20 Gbps, probably a legacy of support for the TB3-to-TB2 adapter.

Edit: A teardown was done a while back on Reddit and Dan Charlton's blog has a summary if anyone is interested.

 

[satcomer]

Also look at MonoPrice 48 bit HDMI cable as well as the input fro Thunderbolt 4 cable! Then just use the monitor controls to switch between the two connections!

 

[joevt]

Yes, this is correct per the spec. What I'm saying is that I believe that this switch is a very simple device with a high speed mux chip in it that probably can only handle 5.4 Gbps per lane (for a total of 21 Gbps).

The switch must be able to handle 10 Gbps per lane to do 32.4 Gbps HBR3, 10 Gbps USB or 20 Gbps Thunderbolt (actually, Thunderbolt 20 Gbps is 10.3125 Gbps per lane).

I don't think it's at all aware of any of the protocols being sent over it, it just switches the lanes and lines between two USB-C inputs and the output. Someone should do a teardown but it won't be me .

True, it's probably a physical switch. Or maybe it could be a mux chip that can handle 10.3125 Gbps analog switching.

Anyway, with that in mind, I suspect that the reason that it works with some cables and not others has to do with the cable and what the e-marker chip inside the cable tells the host computer it is capable of.

Yes. A path from a source to a device through the switch has two cables - one to the switch and one from the switch. Only one of them should have a e-marker chip. I think the cable to the switch is built-in?

These USB 3 Gen 2 cables that work with it must advertise to the computer a rate that keeps the signal within the tolerance of the switch (whether they're sending 10Gps USB data or Alt-Mode 20Gbps HBR2 DisplayPort).

Minor correction: HBR2 x4 is 17.28 Gbps.

Better cables that tell the computer that they can handle a faster rate are probably causing it to fail.

Right. A 40 Gbps cable probably won't work if the switch adds too much noise. There are some extensions or adapters that can handle 40 Gbps.
https://egpu.io/forums/psu-cables/90-degree-angle-usb-c-adapter/paged/2/#post-66724

What's interesting is that the Mac Thunderbolt controller appears to be able to switch into a non-standard "slow TB3" of 20 Gbps, probably a legacy of support for the TB3-to-TB2 adapter.

Correct. It's the same link rate that Thunderbolt 1/2 uses. Some long/passive Thunderbolt 3 cables are rated only for 20 Gbps. 10 Gbps USB-C cables can be used for 20 Gbps Thunderbolt.

 

[trevor-b]

Also look at MonoPrice 48 bit HDMI cable as well as the input fro Thunderbolt 4 cable! Then just use the monitor controls to switch between the two connections!

How will this work? There's just one input display port in the ASD so we can't use the monitor contols (I think)

 

[trevor-b]

CableDecon appears to work, but the ASD flickers, turns off and on randomly every few minutes

Studio Display shows up exactly as above (Thunderbolt 3, 20Gb/s etc).

This is my setup:

• M1 MBP 14" + cables that came with the DeCon switch
• Switch is plugged into the wall socket via a USB adapter (the iPhone cube)

Perhaps I got a defective switch, it does work for some folks as we've recently seen

I can also try the Yiwentec to see if that is any better.

 

[jacklivehere]

Yiwentec has similar issues. It works great and all of sudden it goes off. I just returned it .

 

[trevor-b]

Yiwentec has similar issues. It works great and all of sudden it goes off. I just returned it .

I wonder how it works for some, but not others (even though the setups are similar, from what I can tell)

 

[edanuff]

I wonder how it works for some, but not others (even though the setups are similar, from what I can tell)

How are you powering it? There wasn’t any power specifications on the switch I received so I used an old iPhone 5V 1 amp power adapter. I’ve been using it for about a week with no issues.

 

[trevor-b]

How are you powering it? There wasn’t any power specifications on the switch I received so I used an old iPhone 5V 1 amp power adapter. I’ve been using it for about a week with no issues.

That's exactly what I tried, the small cube iPhone USB adapter