USB-C Cable Madness

[Analog Kid]

Is there a device that will test and report the standards supported by a particular cable?

I thought the proliferation of USB-B cables was bad, but at least you could tell what you had by looking at it. Now I've got a box full of USB-C connectored cables and I have no idea what standard half of them adhere to. Some have numbers on the connector that clarify it, but many do not. There at least half a dozen standards with the same connector but different capabilities. Is there a way to figure out what kind of cable it is without the trial and error?

I can't tell what's USB 2, 3, 3.1, Thunderbolt, etc, and the more cables I collect the less sure I am what any of them do.

 

[Analog Kid]

Actually, maybe I don't need a special device. I wonder if a little bit of software magic might allow me to do this check with the two TB4 ports on front of the Mac Studio.

I assume the world doesn't collapse in on itself if loop back a USB-C cable between two ports on the same device? The power delivery standards must surely protect against bad things?

 

[xraydoc]

I assume the world doesn't collapse in on itself if loop back a USB-C cable between two ports on the same device? The power delivery standards must surely protect against bad things?

I don’t know — might create a universe-ending paradox or get us all stuck in a temporal causality loop. Better not tempt fate.

 

[Slartibart]

That is an interesting proposal - if you connect 2 USB-C ports of 2 different computers via e.g. the mophie USB-C cable Apple promotes, you connect 2 host controllers.

On modern phones, tablets, (laptops) these are most likely Dual-Role Ports (DRP).

And most DRPs are configured as Try.Source or Try.Sink - one might have a source preference and one has a sink preference and they will always arrange themselves in that manner.

If you connect these via a USB-C cable due to preference one will pretend to be host, the other to be device.

If the DRP ports do not have any preference and you connect them via USB-C cable, they will alternate its CC function trying to pretend as host, then as device, and so forth and a connection will be established.



You see that I set 2 host controllers in bold? I have no idea how many of the ports belong to a single host controller in a Mac Studio. And wether connecting two of them simply crashes the system throwing kernel panics… or whatelse…

If a connection can be established between e.g. the farest separated ports on the back, or between one front and one back port

… IF … ​

you might be able to see a connected »device« in the port device list after opening the MacOS System Profiler telling you even the max. transfer speed… 🤯😱😂🤣


I'll get the Popcorn…

nota bene: regular ports between 2 hosts can be connect via a USB-C cable but no connection will be established.



TL;DR: if you want to know wether your unlabeled cables with USB-C connector support USB 3.x gen x or Thunderbold 3/4 connect an external TB4 device with said cable to a TB4 port on your computer and look up the device lists in Apple’s System Profiler. 😎

​

 

[Analog Kid]

I don’t know — might create a universe-ending paradox or get us all stuck in a temporal causality loop. Better not tempt fate.

I'd swear you'd just said the same thing to me yesterday.

Wait, let me unplug this cable and see what happens...

Oh, that's better!

 

[Analog Kid]

That is an interesting proposal - if you connect 2 USB-C ports of 2 different computers via e.g. the mophie USB-C cable Apple promotes, you connect 2 host controllers.

On modern phones, tablets, (laptops) these are most likely Dual-Role Ports (DRP).

And most DRPs are configured as Try.Source or Try.Sink - one might have a source preference and one has a sink preference and they will always arrange themselves in that manner.

If you connect these via a USB-C cable due to preference one will pretend to be host, the other to be device.

If the DRP ports do not have any preference and you connect them via USB-C cable, they will alternate its CC function trying to pretend as host, then as device, and so forth and a connection will be established.



You see that I set 2 host controllers in bold? I have no idea how many of the ports belong to a single host controller in a Mac Studio. And wether connecting two of them simply crashes the system throwing kernel panics… or whatelse…

If a connection can be established between e.g. the farest separated ports on the back, or between one front and one back port

… IF … ​

you might be able to see a connected »device« in the port device list after opening the MacOS System Profiler telling you even the max. transfer speed… 🤯😱😂🤣


I'll get the Popcorn…

nota bene: regular ports between 2 hosts can be connect via a USB-C cable but no connection will be established.



TL;DR: if you want to know wether your unlabeled cables with USB-C connector support USB 3.x gen x or Thunderbold 3/4 connect an external TB4 device with said cable to a TB4 port on your computer and look up the device lists in Apple’s System Profiler. 😎

​

So, we don't expect things to go "boom" if I connect two ports on the same device together even if they may be on the same controller-- there's a good chance that it's smart enough to not argue "I'm the source!" "No, I'M the source!" and get into an electron pissing contest over the issue?

I'd rather not have to explain my hairbrained scheme to the Genius Bar tomorrow...

 

[Slartibart]

You mean “boom” like white smoke and the smell of lead-free solder tin? No. Not even on USB-A. You need active components. A host and a device.

But I really do not know - I would have tried already with some laptop if at home, but I am actually in the scandinavian "outback" on vacation 🤓

The iPP I carry has just one USB-C port 🤣😂😎

 

[xraydoc]

I once (accidentally) looped back an ethernet cable in to two ports on my full 24-port switch. The cable was buried in the back and I thought each end was something else. Couldn’t figure out why devices started dropping off the network one by one until I unplugged everything from the switch and discovered what I’d done. Spent a good couple hours trying to figure out what was going on.

Sorry to digress…

 

[Slartibart]

I once (accidentally) looped back an ethernet cable in to two ports on my full 24-port switch. The cable was buried in the back and I thought each end was something else. Couldn’t figure out why devices started dropping off the network one by one until I unplugged everything from the switch and discovered what I’d done. Spent a good couple hours trying to figure out what was going on.

Sorry to digress…

Well, at least Intel-based Macs (even PPC… maybe?) - for quite a while - will convert the connection automatically to a crossover connect when done between 2 computers to allow data transfer… actually I do not know wether Apple Silicon does the same.

Any volunteers to use a regula CAT-6 cable to connect 2 Macs - one at least AS - and check wether you can connect and transfer some data?

This thread is getting better and better 🤓🍿🎉🤜🤛

 

[Analog Kid]

You mean “boom” like white smoke and the smell of lead-free solder tin? No. Not even on USB-A. You need active components. A host and a device.

But I really do not know - I would have tried already with some laptop if at home, but I am actually in the scandinavian "outback" on vacation 🤓

The iPP I carry has just one USB-C port 🤣😂😎

View attachment 2041539

Man, that looks like a place one might just forget about cables for a while...

So, yeah, it kinda works, but it's not the easiest. I'm still sorting out the different configurations, but as far as I can tell, 5Gbps, 10Gbps, 20Gbps all seem to show as 20Gbps under the TB4/USB4 headings of System Information. Both ports show they're connected to a Mac Studio. 40Gbps is indicated as such. Old USB2 stuff doesn't show up there at all, but it does show up in the USB section (not the TB4/USB4 section) as 480Mbit connected to a Mac. Only one port shows the connection.

I guess I don't really know how different the 5/10/20Gbps cables really are, but I'd think they'd label them at their maximum, so I'm not sure what to think.

Worth noting: connecting the two ports together sent my CPU usage through the roof. Didn't do any damage as far as I can tell (I hope!), but the system was clearly confused...

System Information isn't the greatest interface for this, but it does suggest there might be a path to someone writing a utility.

 

[Lioness~]

Yep, I was sitting awhile the other night with intention to buy some extra USB-C cables.
Oh man, I was sitting awhile and investigated…..in the jungle.
Figured I have to read up more on this and do some homework.
Good there’s a thread on this 🙂

 

[Slartibart]

Worth noting: connecting the two ports together sent my CPU usage through the roof. Didn't do any damage as far as I can tell (I hope!), but the system was clearly confused...

That sounds like one host controller for both. Actually I have a hunch that it’s always 1 controller for 2 ports… at least not 1 per port because then Apple wouldn’t use “up to” whatever Gb in the technical specs.

 

[Slartibart]

So, yeah, it kinda works, but it's not the easiest. I'm still sorting out the different configurations, but as far as I can tell, 5Gbps, 10Gbps, 20Gbps all seem to show as 20Gbps under the TB4/USB4 headings of System Information. Both ports show they're connected to a Mac Studio. 40Gbps is indicated as such. Old USB2 stuff doesn't show up there at all, but it does show up in the USB section (not the TB4/USB4 section) as 480Mbit connected to a Mac. Only one port shows the connection.

So you connected front to back?

That the TB4 appear all as 20Gps isn’t surprising - it’s probably the default.




TL;DR: It is possible to identify the type of an unlabeled cable with USB-C connectors by simply connecting it between 2 DRP host controller on the same MacStudio and using Apple System Profiler.




Excellent. Thank you very much! This isn’t great… it’s GRAND! 🤜🤛🙃😀

 

[MikeDr206]

The USB consortium is a cluster eff. This idea that USB C is a connector type/form factor, etc. — yeah, try explaining that to someone. And the ”previous name” vs ”current name” — sheesh.

They need to wipe the slate clean and start over, kinda like the Wi Fi folks did. Rename the connectors after mountains or cities or something (Like a certain fruit company did), and then reserve the USB nomenclature for transfer rates.

Thunderbolt is almost as bad … the difference between 3 and 4 (both using “USB C” connectors) is confusing.

 

[MikeDr206]

I’ll add this… they really had bigger issues than worrying about a space. ”USB 3”. “USB4”.

• USB4 was announced in March 2019. It leverages the Thunderbolt 3 protocol and offers transfer speeds of 40 Gbps. (Note that the correct specification name is USB4 as defined by the USB developers. It is often identified as USB 4 with a space.)

 

[Analog Kid]

That sounds like one host controller for both. Actually I have a hunch that it’s always 1 controller for 2 ports… at least not 1 per port because then Apple wouldn’t use “up to” whatever Gb in the technical specs.

I don't think so... The System Information panel shows separate lines for each port, and then it cascades into a tree underneath. I think each line is a controller. I think "up to" is because saying 40 but delivering 38 gets you sued...

But yeah, I think there was some confusion in the drivers about what exactly the machine wanted to do with itself. "What do you want to do?" "I dunno, what do you want to do?" "I'm flexible, so you just decide." "Yeah, but I'm you, so if you're happy, I'm happy." So it just turns into a rambling conversation or a never ending handshake.

I wonder if I cared enough to try it, whether going into network settings and setting up a network on those ports would quiet the demons (daemons?) by giving it a purpose.

 

[Analog Kid]

So you connected front to back?

That the TB4 appear all as 20Gps isn’t surprising - it’s probably the default.

I connected front to front. It's an Ultra, so both front ports are TB4.

An actual TB4 cable shows up as 40Gbps, it's all the USB 3.x cables that pretend to be 20Gbps.

 

[Analog Kid]

View attachment 2041649

The USB consortium is a cluster eff. This idea that USB C is a connector type/form factor, etc. — yeah, try explaining that to someone. And the ”previous name” vs ”current name” — sheesh.

They need to wipe the slate clean and start over, kinda like the Wi Fi folks did. Rename the connectors after mountains or cities or something (Like a certain fruit company did), and then reserve the USB nomenclature for transfer rates.

Thunderbolt is almost as bad … the difference between 3 and 4 (both using “USB C” connectors) is confusing.

I’ll add this… they really had bigger issues than worrying about a space. ”USB 3”. “USB4”.

Yeah, they really made as hash of it. And it's like they started to make a mess and decided "screw it, let's not settle for half assed, let's go for full assed".

To be fair, it takes a special kind of person to sit on a standards committee. I would bet a significant sum that the "space" versus "no space" was a hot topic for debate among the members, most likely because searching with the space is ambiguous, and team no-space won-- and that side is now drunk with power and will not tolerate backsliding.

I used to hate all the different connectors for USB, but I'm starting to see the value now in identifying sub-standard cables. The blue tongue in the USB 3.x A connectors was a good idea at the time, but USB-C just completely hides the details.

Sometimes you can kind of guess by the thickness of the cables-- the thicker the cable the higher the standard. Apple, of course, manages a pretty decent TB4 cable that's reasonably lithe compared to the others and then puts a basic TB logo on there and calls it a day. No Apple logo or TB version marking...

 

[Analog Kid]

Yep, I was sitting awhile the other night with intention to buy some extra USB-C cables.
Oh man, I was sitting awhile and investigated…..in the jungle.
Figured I have to read up more on this and do some homework.
Good there’s a thread on this 🙂

What's got me in this mess is going through the cable box to get rid of everything obsolete-- but it's like Noah's ark, you need a couple of every kind of animal just in case you need to bring up an old peripheral that you forgot you had.

Is there an old FW400 scanner in the basement? Better keep this just in case...

I'm trying to cut down the cable count and just keep a little box of adapters. I can find them for most things except, for whatever reason, USB 3.0 B. I can find the micro-B, but not the regular fat B.

 

[Lioness~]

What's got me in this mess is going through the cable box to get rid of everything obsolete-- but it's like Noah's ark, you need a couple of every kind of animal just in case you need to bring up an old peripheral that you forgot you had.

Is there an old FW400 scanner in the basement? Better keep this just in case...

I'm trying to cut down the cable count and just keep a little box of adapters. I can find them for most things except, for whatever reason, USB 3.0 B. I can find the micro-B, but not the regular fat B.

Yes, I know 😂
I throw out a lot of older ethernet-cables awhile ago, and bought some of newer versions. Not that they are used so often, but it happens.
Boxes of cables is just part of having some tech. Buying some new, throwing out some old...