[HN Gopher] I've made a Cursed USB-C 2.0 device
___________________________________________________________________
I've made a Cursed USB-C 2.0 device
Author : DyslexicAtheist
Score : 235 points
Date : 2021-03-22 11:19 UTC (11 hours ago)
(HTM) web link (twitter.com)
(TXT) w3m dump (twitter.com)
| ajb wrote:
| Hah. This made me go looking for a 'warding fingers cross'[1]
| emoji, but sadly there isn't one.
|
| [1] Like this: https://imgflip.com/memetemplate/153127632/Cross-
| fingers
| Hnaomyiph wrote:
| I feel like USB-C is cursed enough on its own. The sheer number
| of times I've had to explain to family members why just because
| the two USB-C ports on a laptop look the same, doesn't mean they
| work the same.
| airhead969 wrote:
| And why didn't it use a water-/corrosion-proof, breakaway
| magnetic connector?
| gumby wrote:
| Cost. At least the part that wears out first is on the cable,
| not the device. That was one of the botches of mini-UCB A
| legohead wrote:
| I've had more issues with USB-C connections wearing out than
| other formats, even micro&mini-usb.
|
| My phone barely charges at this point, which is frustrating
| because it otherwise performs fine. I'm going to have to buy a
| new phone because of the damn charging port!
|
| I was considering how many times I've actually plugged it in.
| Worst case for me would be 3x/day. At 3 years, that's only
| ~3300 times. Surely they stress tested the connection more than
| that before production? Of course, these days I'm plugging it
| like 20x/day because it falls out or just doesn't work.
| pinkythepig wrote:
| my phone had an issue with charging cables falling out. Turns
| out the port had compacted lint jammed in it. Turned the
| phone off and used a needle to clean it all out, phone
| retains cables now like the day it was new.
| sgtnoodle wrote:
| This. My phone reports "moisture detected" or oscillates
| between charging and not charging when there's crud inside
| the socket. I mechanically scrape it with the tip of a
| sharp pair of tweezers when it's lint, or I use the
| tweezers to swab with little pieces of paper towel soaked
| in isopropyl alcohol when it's something more nefarious.
|
| I don't even bother turning my phone off, but it's rated as
| water resistant and so I am pretty confident that there
| aren't any voltages present when disconnected. Even on non-
| waterproof phones, though, any voltage persistently applied
| to pins on an external connector will result in corrosion
| over time, so it shouldn't be a problem to just
| mechanically scrape gently with a dry metal needle.
| avian wrote:
| I find it funny how people used to complain about the sheer
| number of times they had to explain to family members exactly
| the opposite: "No need to ask. If you can plug it in, then it
| will work. Computers are fool-proof like that. No, it's not
| like the jacks on the hi-fi"
|
| As in, someone got a new mouse and didn't know where to plug it
| into their computer, when in fact there was only one DB-9
| connector on the computer where it will physically fit and it
| would be the correct one.
| m463 wrote:
| Didn't DB-9 also work for early video before VGA?
| avian wrote:
| Monochrome adapters (Hercules) indeed had a DB-9, but it
| was a different gender than serial (COM) ports. Monitor
| output had a female DB-9 and COM ports had a male DB-9.
| gregmac wrote:
| I think this was at its peak when basically every computer
| had only USB 2.0 ports. You pretty much could plug in
| anything to anything, so long as it fit. Not to say there
| were no issues -- USB 1.1 hubs, cable length limits -- but
| they were so incredibly minor compared to today.
|
| USB 3 introduced blue plugs, complicating things slightly but
| still everything basically worked, and if something was
| operating slower than expected it was at least obvious by the
| color.
|
| Then 3.1 and USB-C came out, and apparently USB-IF lots its
| collective mind. Now you have you pay attention to see if
| your ports, cables and devices are "USB 3.0" or "USB 3.1 gen
| 1" or "USB 3.2 Gen 1" or "Superspeed" or "Superspeed 5Gbps"..
| (Btw, trick question: all of those are the _same thing_ ).
| MivLives wrote:
| I don't understand why the color coding plugs wasn't
| brought back for C. The 3.0 vs 2.0 thing was nice, and made
| it easy to tell what I needed to plug into. Now I have a
| phone with a 2.0, a laptop with a 3.1, and a macbook with a
| thunderbold, and my USB to HDMI port only works with one of
| the three.
| saati wrote:
| They break aesthetics and for a lot of people that's more
| important than actual capabilities.
| temac wrote:
| I'm not even sure this was strictly true at one point. As
| soon as PS/2 keyboard vs mouse plugs, you had problems. Plus
| you had (and still have) various audio jacks on the computer
| anyway. Back to the mouse even prior to PS/2 you often had
| COM1 and COM2 and if I remember correctly you actually could
| not replug the mouse on the other port in a plug-and-plug
| way. You also could have very weird video cabling in the 3DFX
| 1 and 2 era.
|
| But yes, I agree the USB-C plug mess is probably the worst.
| It has became worse than what it "wanted" to solve. The only
| way to make it work as broadly advertised again would be if
| all plugs supported all protocols (that make sense for a
| given device) and PD options, etc. on all devices and with
| common cables, at max bandwidth everywhere, but not only I'm
| not sure this is technically possible, this would probably be
| cost prohibitive.
|
| And so what is the point? The net number of ports decreases
| on laptops, and there is no need on most gadget devices
| (beyond data+PD). The only point is for manufacturers to
| economize 50 cts and make the new inferior laptops pass as
| better than the old ones because they use the shinny new
| USB-C plugs. I would be happy if the price was actually 1/2
| of the old models.
| sneak wrote:
| This is true of electrical power outlets (15A/20A), HDMI,
| schrader valves, RJ45 (this one especially!), and many other
| things in life, and I don't think it's very fair to pick on
| USB-C in this manner when it does so many other things much
| better than previous alternatives.
| mauvehaus wrote:
| There are actually different connectors for 15 and 20 amp
| devices in the US under NEMA.
|
| You _do_ see NEMA 5-15R receptacles on 20A circuits in
| residential applications, but that 's probably because most
| appliances don't require 20 amps. A 5-15 connector has two
| vertical prongs, a 5-20 has a horizontal and a vertical, with
| the special case of receptacles with a T slot that fits both
| 5-15 and 5-20 plugs.
|
| It goes a bit deeper than that though: A NEMA 6-20 also has a
| horizontal and vertical prong, but they're reversed from a
| 5-20 so you can't plug them in in an incompatible (and likely
| hazardous) way.
|
| The whole standard is really well thought out. I went down
| the rabbit hole when I got an old table saw with a 6-20 plug
| and had to figure out what the hell to plug it in to (dryer
| outlet, via a "custom" extension cord).
|
| I feel like I haven't seen too many uses of Schrader valves
| that are likely to cause havoc. Most of the use cases for
| them besides tires are pretty obviously special and distinct
| from one another. I mean, I'd hope nobody's ever hooked a
| bike pump up to their air conditioner or a can of R134a to a
| tire...
| mindslight wrote:
| safety nit: By using a dryer circuit (30A), you've got the
| wrong overcurrent protection on the saw. Which means that
| some failure modes could overload the saw, but not trip the
| breaker. The proper ways to do this is to run a new 20A
| 240V circuit, or to incorporate a subpanel with a 20A
| breaker into your extension cord. I don't think the risk is
| severe [0], but you should at least know your setup goes
| against the electrical code. And that the problem would be
| more pronounced if you did the same thing with a 40A/50A
| stove outlet.
|
| FWIW if the nameplate of the motor specifies current draw
| at 120V, you can likely reconfigure the motor to use 120V
| instead of 240V.
|
| [0] take a look at the gauge of a dryer's internal wiring,
| which is regulated by UL/CE and not NEC.
| mauvehaus wrote:
| You raise a couple points I point I hadn't considered.
|
| Rewiring the motor to 115v is probably a no-go, since
| it's a 3hp motor (continuous), which I believe is more
| amps at 120v than could be drawn from a normal circuit.
|
| For safety, I'm wondering what kind of faults wouldn't be
| protected against. The starter has built-in thermal
| protection (heaters), which should protect the motor from
| the unlikely use case where I'm pushing the saw too hard,
| or more likely, a stall on start-up.
|
| The breaker should still protect against shorts. I'm not
| knowledgeable enough to know what other faults could lead
| to an over current fault that one or the other of those
| wouldn't catch.
|
| Would anybody care to educate me?
|
| Also: the most dangerous aspect of a table saw is
| probably not the potential for electrical faults :-)
| sneak wrote:
| > _You do see NEMA 5-15R receptacles on 20A circuits in
| residential applications_
|
| This is, of course, what I was talking about. I do
| appreciate the nuances of the 15/20 T-socket and the
| 6-20/5-20 symmetry; NEMA is super cool (aside from the fact
| that bladed plugs that aren't twist-lock are sort of
| lame/less safe in general, at least compared to the UK
| standard bladed plug). It's a fun rabbit hole to venture
| down: my occasion was having to adapt straight-blade wall
| box receptacles that the electrician installed to the
| twist-lock of the PDUs we had bought.
|
| There's also a fun and confusing mess of competing DC
| connector standards. I haven't decided what 12/48VDC
| connectors I'm going to put into my new house build yet
| (beyond the obviously mandatory 5V USB).
| mauvehaus wrote:
| That's never bothered me, but I guess I see your point. I
| always figured that the point of having a 20A circuit
| with 15A receptacles was so that you can plug in and run
| two 10A devices without popping the breaker.
|
| Stupid question: are there any common household
| appliances that draw 20A? I've only ever seen the T
| receptacles in non-household uses.
| kristiandupont wrote:
| I am reminded of Einsteins quote about making things as
| simple as possible but no simpler. I feel that USB-C is an
| attempt to make things just a bit simpler than possible.
|
| With USB-A and -B, there is a physical indication of the
| direction of flow (data and/or current). Just "connecting"
| two things is sometimes unambiguous, but sometimes it's not.
| thedanbob wrote:
| From what I remember reading about the spec, USB-C feels
| like an attempt to make things simpler for users (one plug
| for everything!) _and_ manufacturers (here 's all the
| things you _can_ do, but they 're all optional!)
| simultaneously, which of course just makes things more
| complicated for everyone.
| BrandoElFollito wrote:
| > This is true of electrical power outlets (15A/20A)
|
| You mean that one can hold 15A and the other - 20A? If so,
| they do work the same, they just have different capacities
| (like a tap, some of them will provide more water, others
| less but they work the same (especially if they look the
| same))
| bellyfullofbac wrote:
| But USB was supposed to be the unifying connector.
|
| Before: "Here in the back of the computer we have PS/2 ports
| (1 for keyboard and 1 for mouse), a parallel port, serial,
| 25-pin serial, game port".
|
| Introducing USB: "Everything is USB now! Plug anything
| anywhere!"
|
| USB version whatever: "Well the sockets look all the same,
| but you can only plug your display in here, to charge it you
| have to connect it here", etc, etc.
| unwind wrote:
| But the point is that USB was introduced more or less on the
| promise of _not_ being like that. When USB 1.1 came in the
| late 90s, it was pretty nice. Lots of different ports and
| cables went away, and all were replaced by standardized USB
| ports and cables.
|
| You could geek out and learn the difference of upstream (A,
| host) and downstream (B, device) ports, the various types of
| B port sizes, and that was it. Later USB 2.0 was introduced
| and just (bam!) made it all 40 times faster, but it still
| logically worked pretty much the same.
|
| Then USB 3.x came and just blew all that to h-ll, which is
| frustrating for both old bearded geeks, _and* new /non-
| technical users._
| mminer237 wrote:
| For consumers, wasn't USB 3.0 just USB 2.0 but a few times
| faster? USB-C is what is confusing to some people.
| Replacing micro USB was straightforward enough, but
| replacing USB-A is a rough process.
| tsbinz wrote:
| USB 3 is also what kills your wifi if things aren't
| properly done (e.g. https://medium.com/ghostbar/your-
| usb-3-0-hub-is-killing-your... - and it's not only a mac
| problem), so it's not just 2.0 but faster.
| mumblemumble wrote:
| I guess?
|
| Except that my desk has three USB cords, each with a color-
| coded label so that I can tell what each one is for. One is
| seemingly the only one that will charge my e-reader, but
| only does low speed data transmission so it never really
| gets used for anything _but_ my e-reader. Another is power
| only and therefore useful for charging devices without my
| computer attempting to talk to them. And a third is a
| proper, modern (ish, I suppose), well-behaved USB 2.0
| cable.
| jdsully wrote:
| 20A plugs look different, they have a prong rotated 90
| degrees.
| cesarb wrote:
| Where I live (which uses the NBR 14136 standard), the 20A
| plugs and sockets look identical to the 10A plugs and
| sockets, the pins and corresponding holes are only slightly
| larger (so that a 10A plug fits on a 20A socket, but not
| the reverse).
| tzs wrote:
| What we need is a reasonably priced dongle that you can plug
| into an arbitrary USB-C port and it tells you what that port
| supports.
| magicalhippo wrote:
| > just because the two USB-C ports on a laptop look the same,
| doesn't mean they work the same.
|
| This is already a solved problem[1] through color coding. Not
| sure why they couldn't use that scheme. Maybe combine a few to
| indicate things like DisplayPort and Thunderbolt capability,
| could have up to four quadrants for example.
|
| [1]:
| https://en.wikipedia.org/wiki/PC_System_Design_Guide#Color-c...
| Piskvorrr wrote:
| Nope. That's a UX fail: "of _course_ they 're different,
| didn't you RTFM and observe the correct color?"
| reaperducer wrote:
| _This is already a solved problem[1] through color coding_
|
| You would think so, but no. Colors don't help.
|
| Not just because a good chunk of the population has color
| vision issues. But people for some reason the average person
| can't latch onto that sort of thinking.
|
| We went through this back in the 90's. Your PS/2 mouse plug
| was one color, and the PS/2 keyboard plug was another color.
| But people still tried to stick them in the wrong places.
|
| Same with the sound card. Microphone, speakers, line in, line
| out, all had their own colors that matched the wires that
| came in the box. Regular people screwed that up all the time.
|
| Going further back to the 70's and 80's, if you looked at the
| back of anyone's rack system, there was a 50% chance they had
| the red/white pairs of RCA plug backwards. Then when video
| started getting carried over the same plug, but colored
| yellow, things got worse.
| tenacious_tuna wrote:
| > this is already a solved problem through color coding
|
| Speaking from experience, I don't think most end users are
| liable to pay enough attention to their ports to notice the
| color coding. I remember family members being confused by the
| blue 3.0 ports when those were a thing--now there's also red
| ones, and different color C ones, and some C ports have the
| little lightning bolt and some don't, and most users don't
| know what THAT means.
|
| The value-add of USB C was supposedly you didn't have to buy
| different cables for different purposes now, you could just
| slap everything on a C port. But of course that's not truly
| the case, and we're now in a messy soup of standards and
| capabilities that even to seasoned tech professionals are
| hard to disentangle, much less for end users.
|
| Calling this a solved problem 'cuz they slapped some colors
| on _some of_ the ports is missing the forest for the trees.
| yarcob wrote:
| Does the bolt mean Thunderbolt or power delivery?
| sgtnoodle wrote:
| My wife's laptop has three USB-C ports and the laptop
| charges off all 3, but only one has the bolt. I strongly
| suspect it means Thunderbolt support, i.e. it's the only
| port that will work well with a dock.
| sgtnoodle wrote:
| I built a new desktop recently, and the case has a USB-C
| port on its top panel. I had to buy a $20 PCI-E card to
| have somewhere legit to plug the port into because my
| motherboard didn't support it. I had the option of trying
| to make it USB 3.1 or whatever, thunderbolt, or USB 3.0 or
| even 2.0 via a series of adapters that probably shouldn't
| exist but do on ali express.
|
| I doubt I'll ever plug anything but a smart phone into it,
| but it seemed worth it for the feng shui.
| dspillett wrote:
| Not when there are many ports out there without the right
| colours. Or with the wrong colours. Or arbitrary different
| colours because some manufacturer has a "bright" idea on
| their own. Or where it doesn't matter (were the keyb/mouse
| ports generally interchangeable? I certainly had two machines
| where they were despite the colour coding and I've seen
| single ports with "key/mouse" iconography since).
|
| Maybe if the next standard has colours to start with, and
| they are unambiguous, and somehow not even ambiguous if
| confused with a previous port version, and they are adhered
| to by _all_ manufactures, consistently, and nothing new
| arrives that someone adds a colour for before the standards
| body makes a decision...
| xoa wrote:
| I feel like this is a temporary state of affairs that falls
| into the bucket of "regrettable but unavoidable". Over time I
| think the standard march of mass manufacture, refinement,
| miniaturization, and so on will result in every single USB-C
| plug on a general purpose device (like a notebook) doing the
| max of the standard. They'll all be Thunderbolt 4/USB 4 or
| whatever, and thus able to do everything. Cables production
| will also scale up and become cheaper, and at some point every
| single cable one would typically find will be capable of
| handling whatever. There aren't any _fundamental_ scaling
| blockers, like some dependency on rare metals or something.
|
| But it's still costly at the start of the refinement cycle, and
| it's hard to bootstrap without allowing manufacturers to do
| cheaper cut down feature versions to get the ball rolling. It
| needs to provide some marginal value in the mean time and real
| promise, even if it means some higher overhead in the
| establishment phase. So for someone buying a new device in 2025
| or 2030, USB-C may still exist but I think issues with what
| ports do what will be lessened. We already see devices like
| Macbook Pros where all the USB-C ports are functional, and
| while those are on the higher end of pricing they aren't
| stratospheric enterprise territory either. I suspect it won't
| take that many hardware generations for that sort of thing to
| spread downward. The question is if that's worth the immediate
| trouble.
|
| And at least for USB-C, I personally think it'll be worth it.
| It's a good connector, and the improved capabilities are
| valuable. We've had USB-A for a long, long time, and it doesn't
| seem unreasonable to guess that USB-C will stick around
| similarly. There was demand for something more compact and
| reversible with other QoL benefits along for the ride, and I
| think it's worth the upfront cost to get the whole industry
| onboard something that can converge rather then ending up with
| various manufacturers going their own routes.
| frosted-flakes wrote:
| There will always be some inconsistencies that consumers will
| need to be aware of. For example, Thundetbolt cables are
| limited in length, to about 0.5 m for passive cables and 1 m
| for active cables (and those are very expensive). Meanwhile,
| a bog-standard charging cable can easily be several metres
| long. I doubt every cable will become an active Thunderbolt
| cable; that's simply not realistic or economical.
| marcosdumay wrote:
| Between USB2, USB2-Power, and USB3, I haven't got a laptop that
| I know what USB port does what in a long time... And I still
| didn't get any with USB-C.
| myself248 wrote:
| To make it worse, there's a Thunderbolt port which is
| indicated by a little lightning-bolt near it, and a charging
| port which is indicated by a little lightning bolt near it,
| and neither of those has anything to do with the Lightning
| connector.
|
| Some USB-C ports have DisplayPort output, so there's a DP
| near them. Some do Power Delivery, so there's a battery near
| them. And some are also a power input to the laptop, so there
| might be other random symbols near them.
|
| It's chaos. I just juggle plugs until I get the expected
| behavior, and sometimes I never do because it's not
| implemented. I've given up.
| medium_burrito wrote:
| The 737 Max quote "designed by clowns, who in turn are
| supervised by monkeys" seems appropriate for USB-C too.
| airhead969 wrote:
| I often have to flip old Lightning cables if there is corrosion
| on one side of the plug contacts. Also, Lightning has a problem
| with dirt and lint accumulation, so the end of a large paperclip
| is useful to clean-out the port on the device occasionally.
| londons_explore wrote:
| USBC can also fail and become unidirectional... I have a bunch
| of cables here that only work one way round on one or both
| ends.
|
| Now there are 4 combinations to try rather than two (flipping
| each end of the cable - 2x2 = 4)
| unilynx wrote:
| Frequent problem indeed with dirt from pockets, but I'd
| recommend a toothpick over something metal.
| airhead969 wrote:
| I've tried that. Toothpicks break off and don't clean the
| gunk. Round cylinders are fine because the contacts are flat.
| There are even keychain metal lightning cleaners that are
| basically just large paperclip-like ends, and that's what
| many Apple store employees use.
|
| Edit: as long as you're not using a needle-like piece of
| metal to dig at or bend the contacts, it should be fine.
| diebeforei485 wrote:
| Cursed Lightning devices exist, most notably internally.
| IshKebab wrote:
| I've actually used a device that used USB-C but still required
| you to plug it in a certain way around. It was a Bluetooth
| protocol analyser. There was an LED next to the socket that only
| lit up in one orientation.
| StavrosK wrote:
| I have devices (two, IIRC) that only charge if they're connected
| in one orientation and not the other. So frustrating.
| sbarre wrote:
| I love the comment that says you could make a device that
| requires you to unplug and plug the other way before it works, no
| matter what.
| sneak wrote:
| At least then the insertion effort is O(1): you know in advance
| it will take two tries. Even that is an upgrade over pre-C USB,
| in my view.
| 2rsf wrote:
| The average tries for USB 2.0/3.0 is bigger than 2, something
| closer to 3
| rightbyte wrote:
| I do prefer mechanical feedback over software feedback.
| cassianoleal wrote:
| Like an electrical shock if it doesn't like the
| orientation?
| TheRealSteel wrote:
| I believe to properly conform to the USB specification, the
| device must be tried one way, tried the other way, then tried
| the first way again before it plugs in properly.
| NoOneNew wrote:
| Calm down there Satan.
|
| Though, in all seriousness, it would make an interesting
| security through obscurity feature. Everything works fine
| with the device, but only allows/shows certain features/files
| after Satan's rotation pattern. More secret squirrel than
| "security" in reality.
| dogma1138 wrote:
| You forget the chicken bones and the tears of a Virgin step.
| fuzzfactor wrote:
| >"I've made a Cursed USB-C 2.0 device"
|
| You and everyone else.
|
| I knew this was not going to be ideal in the late '90's
| when USB 1 came out.
|
| Radio Shack was still going strong but this was the first
| PC connector that you could not purchase plugs or jacks for
| to solder your own. Also no suitable 4-conductor cable.
|
| Even though the USB 1 approach was for a 92 foot maximum
| cable length (since it was only intended for the low-
| bandwidth webcams at the time) this was rapdily
| nonpublicized since USB 2 was already in planning, for much
| faster speed and a 25 foot max cable length, eventually
| shortened to 16 feet.
|
| Well once you got suitable cable, you still had to cut
| pigtails off of USB cords so you could get the cable ends.
| tyingq wrote:
| Two counters tied to an AND gate and you could require X number
| of orientation flips before it works :)
| airhead969 wrote:
| USB-C port knocking... flipping.
| minikites wrote:
| I assume you could add a timer somehow, so you could make it
| like a combination lock where you have to wait X time between
| turns?
| joombaga wrote:
| You could achieve similar results without the added
| complexity by extending construction into 4 spatial
| dimensions.
| weinzierl wrote:
| Now I want a USB-C thumb drive that has different data on
| different sides. Like the old 5 1/4" diskette drives where you
| flipped the disk for double capacity. Using it for retro-gaming
| would be fun. When the game says "Flip the Disk" you flip the USB
| drive.
| yarcob wrote:
| That won't work because the detection logic is in the female
| side, not the male side. You could make a hard disk with
| detachable cable, though.
| progman32 wrote:
| Put an accelerometer in the drive!
| protomyth wrote:
| The 007 version would have data on one side and blank the drive
| if plugged in the wrong way or, well, blow up to provide a
| distraction.
| Yizahi wrote:
| And sides would be completely unlabeled...
| protomyth wrote:
| go with slightly different textures.
| Theodores wrote:
| Given that this is the only practical application you have to
| wonder why we ever had the one way plugs in the first place.
| el_nahual wrote:
| To me it's more baffling that a one-way plug would have a
| (roughly) symmetrical profile. Or even worse, the round
| connectors (like old PS/2 mouse/keyboard connectors).
|
| A one-way plug would be fine if the profile were sharply
| asymmetrical, to the point where one could find the right
| orientation by touch alone. Maybe something like an even more
| pronounced trapezoid than hdmi.
| gumby wrote:
| It was to reduce BOM cost. That is such a driver that there
| were (/are still?) cables without any data lines at all and
| only power, just to save money.
|
| I used them for plugging into public power supplies, but they
| were never sold to consumers labeled for that purpose.
| [deleted]
| chaorace wrote:
| Two major reasons, as far as I understand things.
|
| Firstly, reversible plugs are harder to make structurally
| resilient, they only become feasible cost-wise as stronger
| materials become cheaper and manufacturing grows more
| efficient.
|
| Secondly, reversible plugs are a lot more complex. Compare
| the 4(ish) pins of USB-A to the 24 pins on USB-C. Not all of
| them are strictly necessary for parity with USB-A, but you
| could cut that number in half quite easily if the plug were
| not reversible! Sure, this complexity impacts manufacturing,
| but, less obviously, it also pushes that increased complexity
| onto the USB controller hardware/firmware.
|
| Neither of these issues were necessarily dealbreakers, but...
| for a long time they certainly did conspire to make
| reversible plugs into a pipedream. I have to imagine that
| were always bigger problems to solve and fewer resources to
| work with! We're just now seeing reversible plugs really take
| off because we've finally crossed that magic threshold where
| it makes sense to try surmounting those barriers.
| MauranKilom wrote:
| Assuming the structural issues are solved, isn't it
| literally as easy as doubling each pin in a 180deg fashion
| and shorting each pair? What additional controller
| complexity would this lead to (assuming termination issues
| are solved)?
| coryrc wrote:
| That is exactly how usb 2.0 (LS/FS/HS) devices are
| implemented with USB-C.
| chaorace wrote:
| I suppose there's no reason you couldn't do that. I
| imagine they didn't want to do that because cables (as a
| platonic ideal) should just carry signals from point A to
| point B without fudging anything. When you start to screw
| with that dynamic, you end up with lots of non-standard
| issues that people blame on the standard (I'm reminded of
| contractors jamming two 100mb/s lines through a single
| Cat5e cable instead of just switching on a single
| 1000mb/s line)
| lajhsdfhsdf wrote:
| Not for high speed data (USB3.1 ++). The electrical
| length of the unused pins causes reflections in the
| signal. It's a consequence of the finite speed of light.
| rubatuga wrote:
| Turns out the 24 pins of USB-C are now all used for 20Gbps
| USB 3
| buran77 wrote:
| A standard USB 3.1 type A connector has 9 pins. The
| reversible type C has 3 extra pins (SBU, CC, VBUS), not
| counting the doubling caused by making it reversible. So
| while the reversibility doubled the number of pins, the
| increased complexity of the standard itself tripled it
| (from 4 to 12).
| chaorace wrote:
| Good catch. I should have either compared the 9 pins of
| 3.1 or been more specific in saying 4 pins for USB 2.
|
| Fun fact: USB 2 Mini/Micro connectors actually have 5
| pins (hence my original 4-ish statement). The 5th pin
| doesn't actually go over the wire, it's just used as a
| signalling pin to the controller that tells it if the
| plugged in device is compatible with USB OTG.
| duskwuff wrote:
| > A standard USB 3.1 type A connector has 9 pins. The
| reversible type C has 3 extra pins (SBU, CC, VBUS)
|
| Not precisely. The type C connector has four distinct
| USBSS pairs; the type A connector only has two. This
| allows the type C connector to be used to carry
| DisplayPort or other high-speed data alongside USB.
| buran77 wrote:
| Isn't that a direct outcome of the reversibility aspect?
| [0] Technically it has 2 of everything.
|
| [0] https://upload.wikimedia.org/wikipedia/commons/thumb/
| 0/07/US...
| duskwuff wrote:
| Not everything. The USBFS pair (D+/D-, at the center of
| the connector) is mirrored; the two D+ lines are
| connected together. This is not true of the four USBSS
| pairs -- TX1+/- and TX2+/- are separate, and can both be
| used at the same time for different purposes. The CC1/2
| lines (which aren't mirrored either) are used as part of
| the process to negotiate how these pairs are used.
| drewzero1 wrote:
| This! Even just comparing USB-A 1.0 to what it replaced,
| it's hard to imagine a reversible plug like USB-C having
| been feasible/cost-effective to produce in the mid 90s. The
| PS/2 mouse and keyboard ports had pins of a similar size
| and spacing, but it was hard to orient the circular
| connectors. You could get the connector lined up and twist
| gently until the pins found their holes, but eventually you
| would bend a pin. I remember being very impressed at the
| way USB solved the issue of bent pins, but wondering why
| they didn't just key the connector like a Zip disk (which
| had beveled edges along the top of the disk, and wouldn't
| go into the drive upside-down).
|
| Meanwhile we were connecting printers, scanners, and other
| peripherals using a 25-pin parallel (or sometimes SCSI)
| plug. Granted, the DB-25 was already pretty old at that
| point, but I have to imagine a 24-pin reversible USB plug
| would have been close to that size if it had been developed
| in the 90s.
| mortenjorck wrote:
| This thread makes a convincing case for why the original
| USB connector couldn't be reversible, but there's a
| parallel question I've never seen addressed: Why couldn't
| it have been asymmetrical?
|
| The physical design of FireWire was one of its many
| advantages, in that you could instantly tell, visually
| and by touch, which side was up by the beveled corners on
| one side of the plug. I'm guessing the answer here was
| again cost, that manufacturing an interconnect with two
| 90-degree angles and four 45-degree angles was more
| expensive than one with four 90-degree angles, but I've
| never seen any confirmation of this.
| dingaling wrote:
| > This thread makes a convincing case for why the
| original USB connector couldn't be reversible
|
| The sole reason as stated by Ajay Bhatt, the project lead
| at Intel, was cost. They wanted to encourage mass
| adoption of USB and every cent saved helped in that
| initiative.
|
| The compromise for UX was to make the connector
| rectangular rather than circular, so that there was a 50%
| chance of getting it correctly orientated on first try.
| daniellarusso wrote:
| Also, the circuit board can be made into a connector, which
| is not possible with USB-C.
|
| Lots of cool applications using that technique.
| andrejk wrote:
| Good story about that decision here (they did think about
| making it reversible): https://www.theverge.com/circuitbrea
| ker/2019/6/25/18744012/u...
| Kuinox wrote:
| > Compare the 4(ish) pins of USB-A to the 24 pins on USB-C
|
| This is misleading.
|
| If you want to only cover the USB-A spec with USB-C, you
| need only 8 pins.
|
| I have a cheap USB C on my desk that got 8pins because it
| do only USB and charge.
|
| USB-C can pass HDMI signal on the other pins, which your
| USB-A can't do.
| chaorace wrote:
| Sure, it's misleading. That's why the next sentence
| reads...
|
| > Not all of them are strictly necessary for parity with
| USB-A, but you could cut that number in half quite easily
| if the plug were not reversible
|
| Is 4 not half of 8?
| Kuinox wrote:
| You imply that the USB-C could have only 12 cables. Only
| the USB2.0 pins are duplicated, there is 4GND and 4PWR
| cables for power need, and the rest of the connector are
| not duplicated. If it was not reversible, USB-C would be
| 22 connectors, not 12. Plus USB-A is the only one with 4
| cables, what was used on most phones was USB-B micro
| which has 5 cables.
| [deleted]
| chaorace wrote:
| What are you trying to argue here? All pins on the
| connector _are_ rotationally symmetric. They may not be
| useless, because they still increase overall bandwidth,
| but they are indeed doubled. A non-reversible connector
| would not use this design and there would be fewer pins
| as a result (as much as half).
|
| Also: USB-B micro connectors might have 5 pins, but the
| cable itself has 4 wires. The OTG pin is grounded in the
| connector. This is actually why I said "4(ish)" in my
| original post.
| Kuinox wrote:
| The rotating pair can send independant signals.
|
| Thats why USB-C have more or less the same speeds than
| HDMI, while the HDMI have 22 connectors.
|
| Compare what is comparable, you can't use your USB-A to
| display 4K-60Hz video, but you can with your USB-C, or
| HDMI.
| m463 wrote:
| what about an input side and an output side?
|
| One is Read Only Memory, the other is Write Only Memory (the
| holy grail)
| notacoward wrote:
| I have a 7-in-1 USB-C dongle with this behavior. Some of its
| ports won't work in its natural orientation - logo on top, rubber
| feet on bottom - but will if I flip it. I remember being amazed
| and disgusted by this when I discovered it.
| NelsonMinar wrote:
| I have this problem in practice plugging my Pixel 5 phone into my
| car for Android Auto. The cable only works in one orientation.
| Android Auto is notorious for being very finicky about
| connections; no one's really figured it out but it seems to work
| better with shorter cables and of course higher quality cables.
| I've assumed my particular problem was some quirk of the
| connector fit, but now I'm wondering if it could be related to
| the asymmetry in the data pin design.
| [deleted]
| Tade0 wrote:
| My Galaxy S8 and 60W USB-C charger appear to work like this - I
| often have to do a 180deg turn for the phone to start charging.
|
| They only do that in this combination. Not sure if it's
| consistent though - I should probably mark one side and check.
| rand49an wrote:
| My Nokia phone is the same, it's a broken port I think.
| gpderetta wrote:
| same for my Motorola. It will only charge one one side. The
| best part is that if plugged in on the "wrong side". It is
| great when it runs out of batteries and you have to gamble
| that you plugged it in correctly.
| ars wrote:
| Check for dirt in the phone port. Use a slim piece of plastic
| to clean it.
| noxer wrote:
| >if you encounter problems with your USB-C devices you might want
| to try to flip the connector.
|
| I have a Lumia 950 (one of the first USB-C phones) and a short
| USB-A to USB-C (or apple) cable/adapter.
|
| One orientation does not charge the phone, so hes right it does
| happen.
| danielEM wrote:
| USB, HDMI, Cable ethernet, DisplayPort, PCIe, ... they all use
| differential signals to transmit data, just different protocols.
| We could really and truly have just one type of plug to connect
| everything to everything a long time ago and without proprietary
| licenses. As much as I like what USB-C offers as much I hate it
| and other "stupid" standards that duplicate same function just
| with differnt plugs - transfering data.
| floatboth wrote:
| But it offers exactly things like allocating some lanes to
| DisplayPort.
|
| The unfortunate thing is that Thunderbolt was created, and
| instead of a simple way to make PCIe external, we have this
| Intel-created mess that tunnels PCIe over some cursed "MPLS-
| like network" or whatever it is. And it was completely Intel-
| proprietary until recently. At least now the spec is open.
| williamscales wrote:
| I've asked a lot of hardware engineers why ethernet is not
| simply used for everything.
|
| I've never gotten a real answer, one that involves technical
| reasons. It could be done, but it isn't.
|
| I guess people like having different kinds of cables?
| hctaw wrote:
| Different physical connectors prevents you from frying a device
| that gets plugged into the wrong plug.
|
| We should have different connectors for different data rates
| and power levels. Don't pass the buck to designers, they'll
| screw up.
| [deleted]
| justusthane wrote:
| When I worked help desk, I once found a USB mouse that instantly
| killed any computer it was plugged into. Instant power off.
|
| I also found a laptop power supply that would cause the CPU of
| whatever machine it was plugged into to run at 100MHz. That was a
| fun one to troubleshoot.
| gh-throw wrote:
| 10-to-1 that mouse had a really nasty short in it somewhere.
| mschuster91 wrote:
| Am I reading this right that by shorting the up and down D+ (and
| D-) line as one is supposed to by the spec, one essentially
| creates a HF stub?
|
| Or doesn't the stub matter for signal integrity / EMI because
| it's only a couple of mm and fully enclosed by the shield of the
| plug and the receptacle?
| NovemberWhiskey wrote:
| I think it just means that there's only actually a single
| differential pair for USB 2 so connecting the two "D+"s from
| each side of the connector, and the same for the "D-"s, is
| recommended.
|
| This doesn't work for the super-speed differential pairs
| because they're actually different lanes.
| Sebb767 wrote:
| The tweet with the spec talks about USB2.0 devices, so it's
| probably not as sensitive as higher speed 3.0+ device would be
| (just guessing here)
| totetsu wrote:
| I came across this reversible USB A connection searching for a
| usb power pack with sound for my blind friend. I was curious to
| how they achieved it.
| https://accessibility.energrid.us.com/products/energrid-vs15...
| saagarjha wrote:
| Oh, so like a Kanzi cable!
| linspace wrote:
| I would love an uncursed bluetooth
| a3w wrote:
| "This is not available to you"
|
| Hm HTTP 451, or JS error?
| knorker wrote:
| Common twitter error. Reload the page.
| creshal wrote:
| We have a bunch of cursed USB-C cables that exhibit this
| behaviour. So the orientation matters, but only with some cables
| and only with some devices (that use 2.0)... good luck explaining
| that to office staff. Sigh.
| floatboth wrote:
| Google makes "cursed" devices in production :) The Chromebook
| debug functionality is only accessible in one orientation:
|
| https://chromium.googlesource.com/chromiumos/third_party/hdc...
|
| (but that's with a special cable)
| techrat wrote:
| Can confirm. Suzy Q cable. SparkFun sells one. Had to diagnose
| a Pixelbook that got bricked on an update that Google was
| refusing to warranty. Thought the cable was bad before someone
| in Discord suggested that I flip the plug. Still not sure how I
| feel about a reversible plug having a specific orientation.
| fennecfoxen wrote:
| You feel terrible about it. The question is how terrible.
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