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All About USB-C: Manufacturer Sins

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People experience a variety of problems with USB-C. I’ve asked people online about their negative experiences with USB-C, and got a wide variety of responses, both on Twitter and on Mastodon. In addition to that, communities like r/UsbCHardware keep a lore of things that make some people’s experience with USB-C subpar.

In engineering and hacking, there’s unspoken things we used to quietly consider as unviable. Having bidirectional power and high-speed data on a single port with thousands of peripherals, using nothing but a single data pin – if you’ve ever looked at a schematic for a proprietary docking connector attempting such a feat, you know that you’d find horrors beyond comprehension. For instance, MicroUSB’s ID pin quickly grew into a trove of incompatible resistor values for anything beyond “power or be powered”. Laptop makers had to routinely resort to resistor and one-wire schemes to make sure their chargers aren’t overloaded by a laptop assuming more juice than the charger can give, which introduced a ton of failure modes on its own.

When USB-C was being designed, the group looked through chargers, OTG adapters, display outputs, docking stations, docking stations with charging functions, and display outputs, and united them into a specification that can account for basically everything – over a single cable. What could go wrong?

Of course, device manufacturers found a number of ways to take everything that USB-C provides, and wipe the floor with it. Some of the USB-C sins are noticeable trends. Most of them, I’ve found, are manufacturers’ faults, whether by inattention or by malice; things like cable labelling are squarely in the USB-C standard domain, and there’s plenty of random wear and tear failures.

I don’t know if the USB-C standard could’ve been simpler. I can tell for sure that plenty of mistakes are due to device and cable manufacturers not paying attention. Let’s go through the notorious sins of USB-C, and see what we can learn.

Omitting The Resistors, One Cent At A Time

No USB-C resistors in sight, and the pins aren’t even soldered

Yep, you got it. The first, honorary entry is omitting 5.1 kΩ pulldowns on a USB-C port intended for charging your device. “Why does my device charge with a USB-A to USB-C cable, but doesn’t charge with a USB-C to USB-C cable”, asks the user? The answer is simple – because your device’s designer decided to save one cent while building your device, and didn’t care about testing the device before selling it to you. In other words, your device is supposed to have two resistors connected to the USB-C plug, yet it does not, and USB-C power supplies are unable to detect that they ought to provide power. Remember, the resistor detection is fundamentally a safety mechanism, and by now, information about this problem is omnipresent.

Omitting these resistors is one of the most infuriating Type-C mistakes for users, and often results in people debugging the problem for hours on end. Here’s just an example of a developer who was working with a WCH RISC-V board using a USB-C connector for power, and spent a good few hours due to WCH not bothering to add these resistors. If you buy an USB-C-equipped Arduino Pro Micro or TP4056 board on Aliexpress, it is likely to be resistor-less. Everywhere you look, you’ll find a resistor-less device or two. The sheer volume of this problem is, honestly, ridiculous.

Murderous “USB-C” PSUs At Your Local Lidl

Remember the power article, specifically, how you get to higher voltages? Let’s recap: you get 5 V first, and then only after resistor detection. Higher voltages require negotiations over a digital protocol. This is a safety rule – it’s how you can use the same USB-C charger for your laptop, your phone, your wireless headphones, your devboards and whatever else.

Picture by Stephanie Lahs

Now, what happens when someone builds a power supply with a fixed higher-than-5 V output, say, 12 V, and puts a USB-C plug on it? The answer is – seriously bad things happen. Such a power supply isn’t safe to be used on actual USB-C devices – it’s likely to destroy your phone or laptop, and it’s at a glance indistinguishable from an adapter that follows the USB-C rules laid out for everyone else. If you must use such an adapter for something every now and then, you ought to mark its cable with red tape in a way that covers the connector plug, so that you (or your loved one) don’t grab it to charge something else. Seriously, it’s easy to make a mistake, and the more you get comfortable with USB-C, the more likely you are to make it.

Who does this? Well, many no-name manufacturers do, but also Lidl Parkside tools, for one. CrowPi does this too, in their recently released CrowPi L laptop. Both of these come with dumb “USB-C” 12 V power supplies, and neither of them should be sold to consumers, especially given that the CrowPi laptop is designed for kids and educational purposes, and Parkside tools are designed for non-tech-savvy people. When your kid burns a $500 smartphone or your granddad burns his laptop due to a $2 power supply, that’s when the gravity of this standard violation really sets in.

Blaming Companies? It’s Not That Simple

The resistor omission is by now a thorn in consumers’ sides, and the murderous PSU designs are unforgivable. Designers should not do these things. There is, however, an area where I can forgive mistakes happening, and that’s the USB-PD protocol – specifically, the compatibility mistakes, especially in early USB-C tech.

The PD specification is 800 pages – this is, no doubt, intimidating. If you’re getting paid to implement USB-C, however, it’s your job to be familiar with it. On the other hand, when you’re an early adopter implementing a complex specification, it’s quite likely you’re going to screw it up through no fault of your own. You don’t have as many implementations to work with, you’re going to work with (and around) similarly early adopter low-level hardware like ICs, and other devices around you are going to be similarly crooked in subtle ways. The gist is – early adoption of is more of a tricky engineering problem than we might recognize.

In addition to that, there’s two early adopter routes for a wide-reaching interfacing technology like this. One route is – you build a device that is engineered to be specifically compatible with the pricey peripherals that you manufacture, despite being based an open standard being aimed at intercompatibility, and don’t really test the device with other things. I call this the Nintendo Switch route, for no particular reason.

The other early adopter route is – you design a device, then test it with other devices. It’s the early adoption stage, so other devices are often similarly broken, and you end up adding a slew of workarounds and bugfixes piled up on top of each other. New devices keep getting released, and for a while each of them brings a slightly more broken implementation. At best, you spend plenty of time testing when hardly anyone else around does, ensuring tip-top compatibility – provided you can throw developers at the problem. At worst, your fixes create a whole new kind of buggy device.

With this “blaming companies” disclaimer in mind, let’s move to the next point, where I will spend time blaming companies.

Not Testing PD Implementations Enough

Nowadays, there’s no excuse to release a poorly tested USB-C product. If an open-source project can have an array of power supplies to test a USB-C PSU with, large companies have no excuse. If you bought a hefty powerbank that doesn’t put enough effort into figuring out power roles and ends up getting charged from the laptop when you need the opposite, that means it’s not been tested on laptops like yours, and chances are, yours isn’t special. Let’s face it – a company developing powerbanks can afford to buy a few laptops with different OSes and test the behaviour until it works well.

The PD compatibility problems are out there, and you might stumble upon them eventually, especially when it comes to charging. There’s laptops that don’t work with specific chargers, for instance – my Framework laptop doesn’t work with a Xiaomi laptop 65 W charger, in a way where the battery keeps cycling from 10% to 30%, and the charger keeps doing connect/disconnect cycles. I also have a dock where charger passthrough works only for half of laptops. Of course, there’s ways to mis-manage specifications, but let’s face it – there’s gotta be a more fundamental cause for this.

Part of the problem is lack of information sharing. When a large open-source project solves a tricky compatibility problem and adds a workaround, it goes onto GitHub for everyone to see and make use of, with a searchable description of the problem in the commit message.

When a commercial entity fixes the same bug, it is thrown into /dev/null for all other informational intents and purposes, except for the binary blob they push as a firmware update – if even. In this case, each company implementing PD-talking stuff, has their own database of PD quirks, working around peculiarities of devices they tested with. Those PD quirks ought to be openly available information, but they’re not.

Proprietary solution developers aren’t paid to share things, whereas in open-source project, the sharing happens naturally, through no extra effort, once again exposing the fundamental inferiority of proprietary processes. Large part of the reason you have buggy USB-C devices, is that companies would rather make you overpay and suffer incompatibilities, than put effort into sharing information between themselves. Whether it’s security vulnerability information or designing standards together, large corporations are slowly learning to do things the right way, domain by domain, but the general concept never really seems to stick – the fundamental blinders of profit motives and greed are just that strong.

Microcontrollers with PD peripherals are often tough to work with, too. Again, this is a lack of effort put into making those peripherals friendly for developers, whether through better design or better documentation – often, more open code, as you might be able to guess, sadly. This factor alone makes it more likely that the end-user will encounter mistakes, purely because a peripheral that is harder to work with will be harder to write reasonable code for.

Don’t Add, Don’t Tell

You can buy a $1000 laptop, and find out that its USB-C port only does USB3 – no charging or DisplayPort. Or, you can buy a mid-tier $500 smartphone, and find out that it can’t charge and do OTG at the same time, despite USB-C making it so that devices can easily do precisely that in a standardized manner, killing off all those MicroUSB splitter adapters with weird resistors on the ID pin.

By Ilya Plekhanov, CC A-SA 4.0

In laptop space, Asus is one of the worst offenders, having had a long streak of devices with only USB3 output on USB-C – no DisplayPort, no charging, not to even mention Thunderbolt. What’s worse – when looking at documentation, you might not find any mention of what the USB-C port is capable of, no matter if it’s capable of something or not. And of course, lack of clear labeling of ports makes it worse.

The cherry on top is a single USB-C port on a laptop – and nothing else — you might have seen Macbooks like this. You’re basically required to carry a dongle with PD passthrough around, there’s nowhere to plug your wireless mouse receiver in, and the USB-C port becomes the living definition of the word “bottleneck”. When it comes to right to repair, having a single USB-C port for absolutely everything means adding a giant failure point that will leave you laptop-less if you accidentally use too cheap of a charger and end up melting the only port’s plastic. If it’s not a Macbook, good luck finding a replacement port; custom-made small-batch USB-C ports can be quite literally impossible to find for a hobbyist.

Still, Workarounds Exist

Remember: if your USB-C cable is broken or wonky, you should stop using it and buy a replacement. Mark devices that misbehave, and talk online about them; name and shame liberally. Read online reviews if compatibility is what you worry about, scroll down on Aliexpress, or search the product name to see if the device you’re buying has the resistors it needs. When buying a USB-C power supply or an expensiveish dock, it can be good to test it with your device and make sure you can return it or exchange it for a different one. With time, the sharp edges will smooth out, and whenever it is that USB-D visits our households, you will find a lot of people feeling nostalgic about just how simple USB-C was.

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44 days ago
My (work) Acer laptop will not charge from an Acer USB-C dock (the dock is too new!). It will charge via a ThinkPad USB-C charger. Sigh.
Victoria, bc
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Bizarre new form of ice might be "true glassy state" of water

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Regular ice with stainless steel balls, about to undergo a process called ball milling which created a brand new type of ice

Ice and water might not seem very exciting to most of us, but they’re actually super strange from a scientific standpoint. Researchers have now discovered a brand new type of ice that’s described as being a true “snapshot” of water, and may be found on alien worlds.

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46 days ago
Ice Nine
Victoria, bc
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Large sofa stuck on small staircase

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Installers in Bournemouth, England, left a large sofa wedged in the turn of a small staircase. The homeowner is upset, reports the BBC.

Luke Ansell ordered the sofa from online retailer designersofas4u.co.uk after moving in to a brand new house in Bournemouth.

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57 days ago
Victoria, bc
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Chonky Palmtop

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384 days ago
I wonder if the number of typos in the project description is indicative of the keyboard layout
Victoria, bc
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How a small change in traffic light signals can reduce collisions with pedestrians by 15%

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By activating the "walk" light for pedestrians a few seconds before the traffic light turns green reduces the likelihood of pedestrian collisions by 15%. The main reason: it's easier for drivers to see walkers in the middle of an intersection than walkers stepping into the street from the curb. — Read the rest

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429 days ago
Saanich is doing this
Victoria, bc
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Sulfur Hexafluoride: The Nightmare Greenhouse Gas That’s Just Too Useful To Stop Using

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Sulfur hexafluoride (SF6) is not nearly as infamous as CO2, with the latter getting most of the blame for anthropogenic climate change. Yet while measures are being implemented to curb the release of CO2, for SF6 the same does not appear to be the case, despite the potentially much greater impact that SF6 has. This is because when released into the atmosphere, CO2 only has a global warming potential (GWP) of 1, whereas that of methane is about 28 over 100 years, and SF6 has a GWP of well over 22,000 over that same time period.

Also of note here is that while methane will last only about 12.4 years in the atmosphere, SF6 is so stable that it lasts thousands of years, currently estimated at roughly 3,200 years. When we touched upon sulfur hexafluoride back in 2019 in the context of greenhouse gases, it was noted that most SF6 is used for — and leaks from — high-voltage switchgear (mechanical switches), transformers and related, where the gas’ inert and stable nature makes it ideal for preventing and quenching electrical arcing.

With the rapid growth of highly distributed energy production in the form of mostly (offshore) wind turbines and PV solar parks, this also means that each of these is equipped with its own (gas-filled) switchgear. With SF6 still highly prevalent in this market, this seems like an excellent opportunity to look into how far SF6 usage has dropped, and whether we may be able to manage to avert a potential disaster.

Best at Not Doing Anything

Sulfur hexafluoride (SF6) skeletal formula
Sulfur hexafluoride (SF6) skeletal formula with dimensions.

What makes SF6 such an excellent, one-stop shop choice for quelling electrical arcs and insulating high-voltage electrical system is because of its stability. Generally, it does not readily interact with other substances, which leads to its properties of being colorless, non-flammable and non-toxic. Unfortunately, this lack of chemical reactivity also means that it can hang around in e.g. the Earth’s atmosphere for a very long time.

Although SF6 occurs naturally, the overwhelming majority is produced by humans, for use in industrial processes and medicine, but primarily in high-voltage electrical systems as a dielectric gas. The main purpose of a dielectric gas here is to increase the breakdown voltage so that higher voltages can be used in less space, generally relative to air.

For when some arcing does occur, the purpose of the gas should also be to quench the arcing, which is where SF6 shines. Although a small part of the gas may be broken down into the toxic S2F10 (disulfur decafluoride), most breakdown products will quickly reform into SF6, which makes it a low-maintenance choice for switchgear. Especially for gear that ends up being installed somewhere remote and relatively inaccessible, this is a very helpful property.

Because SF6 is non-toxic and has a high molecular weight, it has also found use as an inverse party gag to helium: where helium’s low molecular density makes for an increase in perceived pitch when speaking through a helium-filled medium, breathing in SF6 will significantly lower the pitch of one’s voice until the gas has been expelled from the person’s airways.

Gases Want to Be Free

The growth of sulfur hexafluoride (SF6) in Earth's atmosphere during years 2000 -2020.
The growth of sulfur hexafluoride (SF6) in Earth’s atmosphere during years 2000 – 2020. (credit: AGAGE)

An unfortunate side-effect of our planet’s gaseous atmosphere is that any gases which escape from containment, or which are released through human activity end up joining said atmosphere. How concerned we should be about this depends on the gas in question. When CFCs were found to be rapidly eroding the Earth’s ozone layer, this made it crucial to immediately eliminate any significant release of this gas. This was accomplished via the Montreal Protocol, which saw a rapid cessation of most uses of CFCs.

In the case of SF6, it would seem fair to ask just what the scope of the threat is. To assess this we can look at AGAGE’s data. This is the Advanced Global Atmospheric Gases Experiment, which keeps track of a wide range of gases in the atmosphere. Their findings are that the amount of SF6 has significantly increased since 2000, increasing from about 4 ppt (parts per trillion) to around 10 ppt by 2020, with a linear increase becoming noticeable around 1970. Pre-industrial troposphere levels were roughly around 54 ppq (parts per quadrillion).

As over 80% of the SF6 that is produced is used in the electrical power industry, this is also not surprisingly the biggest source of leaks. Much of this is due to the distributed nature, instead of the gas being used in a closely monitored industrial process, items like switchgear are located literally around the world, in deserts, at the top of wind turbines and in the middle of fields. When being installed, repaired or decommissioned, switchgear can also be damaged, with SF6 gas escaping into the atmosphere.

Top-down inversion emission estimate for western Europe (2013–2018).
Top-down inversion emission estimate for western Europe (2013–2018). (Credit: Simmonds et al., 2020)

In a 2020 study based on the AGAGE findings titled The increasing atmospheric burden of the greenhouse gas sulfur hexafluoride (SF6), Simmonds et al. cover the past 40 years of measurements. They note five main source of SF6 leakage:

  • Electrical power industry
  • Magnesium industry
  • Aluminium industry
  • Electronics industry
  • SF6 production itself

As for the major SF6-emitting countries, these were deduced from measurements to be primarily China and South Korea in East-Asia, and Germany in Western Europe. In the case of Germany semiconductor producers are suspected of being major contributors.

As for high-voltage gas-insulated switchgear (GIS), these use as mentioned >80% of the annual production of SF6, with medium-voltage GIS another 10%. These GIS tend to have a lifespan of 30-40 years, with new SF6-based GIS being installed even today, each of which will suffer some level of leakage during normal operation due to the imperfect nature of seals. In the magnesium, aluminium, and semiconductor industries, leaks have been gradually reduced over time, but are still a significant source.

In 2018, global emissions of SF6 were 9.0±0.4 Gg yr−1, with 2018 CO2 emissions being 33.1 Gt (33,100,000 Gg). Taking into account the much higher GWP (22800) of SF6, this makes its 2018 emissions equivalent to about 205,200 Gg, or 0.6% of annual CO2 emissions. While not an astounding number, we must take into account here that so far the emissions of SF6 are increasing year over year. Any SF6-based GIS or similar installed today will be adding to this total for the next decades, while contributing to global warming for a longer period than the industrial era so far.


Clearly, replacing SF6 and generally preventing it from leaking into the atmosphere is a good thing, then. Perhaps ironically, SF6 previously replaced the use of oil in switchgear due to toxic and otherwise harmful substances, and some of the suggested replacements for SF6 are themselves not as benign as this gas. Where possible, one of the best options is a vacuum, with a high vacuum providing very high dielectric insulation.

Maintaining a high vacuum is not easy, especially not over years, leading to alternatives ranging from plain air, CO2, and various fluoride-based substances. Recently Owens et al. (2021) as researchers at 3M published a study on two SF6 alternatives which 3M sells commercially. Their commercial names are Novec 4710 ((CF3)2CFCN) and Novec 5110 ((CF3)2CFC(O)CF3), both being fluoronitrile and fluoroketone mixes.

The idea is that such mixes are added to CO2 or air inside the GIS, to improve the dielectric properties. In this configuration, Novec 5110 with air mixture looks pretty decent, with a (100-year) GWP of <1, but Novec 4710 with CO2 mixture has a GWP of 398, which is better, but not great. SF6 also showed an overall better cold weather performance, down to -38 °C, compared to -27 °C for Novec 4710/CO2, and 0 °C for Novec 5110/air.

US sulfur hexafluoride market.
US sulfur hexafluoride market. (Source: Grand View Research)

This highlights the complexity in replacing SF6 in GIS applications, as each part of an electrical grid has different temperature ranges and other factors that would be a particular SF6 alternative more attractive. With SF6 being relatively cheap, universally applicable, and its use so far unencumbered within the electrical power industry — even within the EU’s F-gases regulations — it’s little wonder that the SF6 market keeps growing year over year.

Not Just SF6

The fluorinated gases have in common that they tend to be man-made, popular in industry and other applications, and have a high GWP. They include HFCs, PFCs, SF6 and NF3. Of these, HFCs are popular in refrigeration, where they replace the previously popular CFCs, along with a number of other gases. Through their production, use and eventual decommissioning, a significant amount of these gases end up in the atmosphere, where they contribute to the specter of anthropogenic global warming.

Looking at the popularity of these gases, the difficulty in finding replacements, and the push to produce more and ever cheaper refrigerators, wind turbines, and distributed power systems, it seems unlikely that we’ll be seeing a major change here. Meanwhile every day sees more of SF6-based GIS and kin being installed in the world’s rush to decarbonize and expand the electrical grid, where they’ll continue to be a problem for decades to come.

Although this is a perhaps depressing perspective, some hope can be gained from the way the world came together to banish CFCs when it was clear that they formed an existential threat to all life on this Earth. Here is to hoping that we can do that a few more times.

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499 days ago
A balloon full of SF6 thuds to the floor. Doesn’t this mean that any SF6 released to the atmosphere won’t get up to the ozone layer?
Victoria, bc
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