Official announcement: https://usb.org/sites/default/files/2019-03/USB_PG_USB4_DevU...
USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB
151–160 of 279 posts
Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB
#152Earlier quoted context omitted.
PCI Express is already working at those data rates.
Computer cases are electrically insulated.
As any radio amateur will tell you, PC shielding in the wild is generally poor. Plus the vast majority of PC RFI is radiated via the connected cables ( be that USB or the power cable ) or the monitor which form broad-spectrum antennas.
A PC and its appendages is a horrendous radio squawk-box and should be kept away from anything RFI-sensitive. The FCC 'must not cause harmful interference' clause is pretty worthless.
Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB
#153Earlier quoted context omitted.
> At the physical layer, is it the materials in the cables are getting better? Yes, and more expensive on that. Laptop makers totally hate usb 3.0+ for that. The industry standard for internal digital connectivity was the FPC - flexible printed circuit board, a very economical and ergonomic solution, but then came USB 3.0. Regular polyimide FPC can't reliably handle the high frequency signalling. Still, many laptop m…
Thanks for sharing and interesting industry perspective. Color me unconvinced on one point though: > Only very recently, there came an FPC maker that makes custom cabling with some proprietary dielectric that can handle 3.0. A brief glance at IPC-4203A (which has been around since 2013) tells me this is a consequence of market cost sensitivity, not one driven by the inherent performance limitations of available mater…
It's more to finding FPC factories dealing with anything amounting to a "specialty product," and finding somebody who can engineer that FPC with all attention needed to signal integrity and fickleness of high frequency circuits.
Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB
#154Earlier quoted context omitted.
> With USB 3.0 they added 4 more signals for separate transmit/receive So is it not actually serial any more?
Serial/Parallel have commonly accepted technical meanings in the context of data interfaces which aren't necessarily intuitive. Parallel refers to taking a raw bit stream and sending N bits at a time down N wires to a receiver who reads N bits at a time and reconstructs the bitstream. This was a common technique in the early days of computing because it is very simple to implement and low clock speeds meant it was of…
Great explanation - thanks!
Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB
#155Does this also mean that soon every computer will be making noise/radiating waves around 40GHz? Can someone with more depth in this area shine some light on this?
I think the signaling is more like 10 GHz and data is scrambled to spread EMI over a wide range.
Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB
#156Earlier quoted context omitted.
Nope. Much simpler. Just enabling the use of the other data lanes that were already in the cable waiting to be used one day. USB-C has 4 differential twisted pair data lines.
Not 'just' at all. USB 2 has a single twisted wire pair, specced for moderate speed. USB 3 replaces that with two pairs with much tighter requirements, one for transmit and one for receive. This involves a tenfold speed boost (.5Gbps to 5Gbps), with much more modern transceivers using much higher frequencies on much better wires. But it also drops the length a single passive cable can be from about 5 to 2 meters. USB…
Now, if only someone would actually ship a USB-C 3.2 (or Thunderbolt) active cable. :(
I have a couple of situations I would like a 7m-ish Thunderbolt 3 cable but can’t seem to find one, even for the multiple-hundreds it would probably cost.
Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB
#157What's optional? That's the most important thing to know is what's optional in the spec. That could make it great or a major pain. I'm referring to how many features the specification defines as "optional" for manufactures and that the USB organization requires for logos. This is why even USB-C is a nightmare. Consider a USB-C cable or device port. It could be charge only, data only, monitor support. There are even m…
I very much agree with you. I've deliberately avoided USB-C for this very reason. It's not that hard - I don't buy new gear very often, and I'm still using an old 5th-gen iPod every day - but there will be a day when I don't have much of a choice anymore. Bluetooth headphones, external hard drives, game controllers, media players, phones... The worst part about USB-C is that it can be implemented so wrong it bricks y…
> The worst part about USB-C is that it can be implemented so wrong it bricks your device!
The miswiring that bricked his device, swapping GND and VBUS, could also happen with older USB plugs. There's nothing specific to USB-C about it, USB plugs have a defined polarity for the power pins since the very first version of the standard.
Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB
#158Does this also mean that soon every computer will be making noise/radiating waves around 40GHz? Can someone with more depth in this area shine some light on this?
Is tinfoil-hatesque EMF poisoning real? I personally believe that it is real (just go camping where there's no service and you'll feel better) but it's hard to prove without decades of study and money, which won't happen because there's so much money to be made. There are other reasons why camping makes you feel better. Earthing/grounding gets you in touch with the earth's natural schumann resonance (through the canv…
I dunno, but turning my home circuit breakers off does make me feel better
Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB
#159Is it an unpopular opinion that USB is already fast enough and has enough features and USB implementers should instead work on cost reduction and compatibility so that we can all move away from USB 2 and pre-type-C connectors?
It's not fast enough. USB cannot drive a 4k monitor at 60hz. You can use the physical interface to do it, but this uses Thunderbolt. This means that the dream of a one-cable-for-everything setup is not here yet, unless you use a Thunderbolt dock, which multiplexes the USB stuff in with the monitor signal. A thunderbolt dock costs around 10x more than a simple USB dock.
Re: USB4 Specification Announced: Adopting Thunderbolt 3 Protocol for 40 Gbps USB
#160Earlier quoted context omitted.
I very much agree with you. I've deliberately avoided USB-C for this very reason. It's not that hard - I don't buy new gear very often, and I'm still using an old 5th-gen iPod every day - but there will be a day when I don't have much of a choice anymore. Bluetooth headphones, external hard drives, game controllers, media players, phones... The worst part about USB-C is that it can be implemented so wrong it bricks y…
> The worst part about USB-C is that it can be implemented so wrong it bricks your device! The miswiring that bricked his device, swapping GND and VBUS, could also happen with older USB plugs. There's nothing specific to USB-C about it, USB plugs have a defined polarity for the power pins since the very first version of the standard.
Mitigating hardware damage is also the responsibility of the device manufacturers. Any external cable carrying power could experience a short circuit due to a fault. All USB hosts are required to limit current to deal with that. If they fail, it isn't the cable's fault.