USB Type C - One step forwards, two steps back? - Page 1
Forum section: electronics / general

author: Howardlong
author_rank: Super Contributor
timestamp: March 05, 2019, 01:04:44 pm
content: I've been using USB Type C as a consumer increasingly over the past two or three years, to the extend where I have three laptops that only have USB Type C, one of which I use as a daily driver when out and about.By far the biggest problem I have with these connectors is their fragility, both electrically and physically. All three laptops have suffered failed USB C connections, two physical and one electrical.A second problem is that these ports try to do too much. Power Delivery, Displayport, Thunderbolt, USB. Only USB is mandatory, the others are optional. Consumers are inevitably going to be confused. I was really surprised, for example, when I discovered that the cyclops single port Apple Macbook didn't support Thunderbolt as that's been one of Apple's big things since its inception.A Thunderbolt dock won't work with a non-Thunderbolt USB Type C host, but a USB Type C dock will work on both a Thunderbolt and non-Thunderbolt USB type C host.If you have a non-Thunderbolt USB Type C host port that supports 4K60p video, you won't be able to run USB 3.0 speeds through it at the same time, only USB 2.0.Add to this that not all USB 3 cables are the same. Not all support Power Delivery, and when they do, they rarely support USB 3.0. The vast majority don't support Thunderbolt. Some cables have varying degrees of embedded electronics inside them, from a simple resistor to marking identification to more complex signal equalisation and amplification.Even Power Delivery is fraught with compatibility problems, and devices seemingly being compatible only sometimes, apparently at random. Some PD marked cables have been known to fry ports.For even a tech savvy consumer, USB Type C is a minefield. Trying to put everything into a single universal connector was a noble goal, but I fear the market has been confused by it all.Of course there are benefits of USB Type C, the reversible cable being the most obvious. But with the concerns I noted in mind, I am really reluctant to put USB Type C on any new products, I feel that the risk and cost of returns is just too much to include into a new product's business model at the present time.

author: tooki
author_rank: Super Contributor
timestamp: March 05, 2019, 04:05:37 pm
content: Quote from: Howardlong on March 05, 2019, 01:04:44 pmThat's an understatement. The idea was great, but it forgot about one simple truth: keyed connectors to ensure compatibility (or rather, to block incompatibility) is a good thing. The mess this has resulted in is kind of epic in its insanity.As for some technical things:I don't even think USB signaling is mandatory in a USB-C connector, insofar as Thunderbolt devices don't support being connected to a computer via USB.But Thunderbolt is, in a sense, a special case, in that other than sharing the connector, it's really a totally unrelated standard, in that both ports must support it, AND a Thunderbolt cable must be used (and a Thunderbolt cable cannot be used for USB.)What's insanely confusing to people is that USB-Cisn't a numbered version of USB, but rather what I'd call a sister standard.Ignoring the mini and micro variants (and the added-pin variants for USB 3.0), USB essentially has 3 kinds of connectors:Type-A (used on the host end only)Type-B (used on the device end only)Type-C (host or device)In theory, any two of these can be combined into one cable, though only USB-C can be on both ends of thesamecable.And then we've got the numbered USB versions, which cover the speeds and features:USB 1.1USB 2.0USB 3.0USB 3.1USB 3.2Oh but wait, each version can have multiple speeds within it. Here's the bitrate, original connector types, and "marketing name" for the speed:USB 1.1:1.5Mbps, A/B: Low Speed12Mbps, A/B: Full SpeedUSB 2.01.5Mbps, A/B: Low Speed*12Mbps, A/B: Full Speed*480Mbps, A/B: High Speed*these two modes are simply the USB 1.1 modes. So yes, manufacturers could, and often did, brand their 12Mbps devices as "USB 2.0" even though it's actually unchanged from USB 1.1.USB 3.05Gbps (full-duplex), A/B: SuperSpeed USBUSB 3.15Gbps (full-duplex), A/B/C: SuperSpeed USBUSB 3.1 Gen 25Gbps (full-duplex), A/B/C: SuperSpeed USB10Gbps (full-duplex), A/B/C: SuperSpeed USB 10GbpsUSB 3.25Gbps (full-duplex), A/B/C: SuperSpeed USB10Gbps (full-duplex, single-lane), A/B/C: SuperSpeed USB 10Gbps10Gbps (full-duplex, dual-lane), C: SuperSpeed USB 10Gbps20Gbps (full-duplex), C: SuperSpeed USB 20GbpsOh but wait, didja notice how above I said "original connector types"? Yep, that's because USB-C also supports older USB standards. Perfect example is how many mobile phones use USB-C, but with only USB 2.0 (High Speed).And then as you said, Power Delivery is overlaid on top of all that, with various combinations of device, charger, and cable producing different charging results.Other than for Thunderbolt, I expect that premium cable manufacturers will start marketing "universal" USB-C cables that have all pins wired, and have thick power lines and are correctly configured for full-power Power Delivery.What devices do you use where you've broken the USB-C connectors? This is honestly something I haven't been hearing much of, leading me to think that it's substantially more robust than earlier mini/micro-USB connectors. And (be honest with me, it's just curiosity, not judgment) are you someone who tends to be easy or rough on your equipment?

author: Howardlong
author_rank: Super Contributor
timestamp: March 05, 2019, 05:50:32 pm
content: Quote from: tooki on March 05, 2019, 04:05:37 pm(1) About a year or so ago, I was fumbling around a Dell XPS 12 9250 that sports two USB Type C (both ports with Thunderbolt, PD and DisplayPort Alternate Mode). I didn't realise it was a Lightning cable I was trying to plug in (doh!) and managed to partially physically break the receptacle in the process. It sometimes works for charging, but it's intermittent. Under the microscope, one of the VBUS connections is visibly broken. As the other port works fine, and I only really use the machine for content consumption, I've not tried too hard to fix it.(2) A few weeks ago, I managed to electrically damage the only USB Type C port on a Macbook 12" Retina, I still don't know how, but is led to a logic board change. It charged, and USB 3.0 worked, but not USB 2.0. At least on this machine, if it's physical receptacle damage, it's a relatively (!) inexpensive cable assembly. Sadly, the problem was electrical.(3) While the Macbook was being repaired, I bought a loaded 2nd hand Dell XPS 13 9365 2-in-1 for a bargain price of ~US$750. The left hand USB Type C port won't support Thunderbolt or USB 2.0, but it does support USB 3.0 and charging. I haven't spent any time trying to fix it, other than visually the port looks undamaged, so I'm unsure whether it's a physical or electrical problem but I suspect the latter.

author: ajb
author_rank: Super Contributor
timestamp: March 05, 2019, 07:03:19 pm
content: USB nomenclature hasalways been stupid, and will continue to be stupidfor the foreseeable future, but the backwards compatibility has never been a bad thing. Would you WANT to have 6 different kinds of mutually un-mateable connectors for all of the different speed capacities, on top of the existing mini/micro/full A/B/C connectors?The Thunderbolt/USB 3.x confusion will hopefully go away in another year or two, asThunderbolt has been transferred to the USB-IF, and will become the basis for USB4.I don't think we'll see USB C entirely displace A and B connectors, at least not until connector manufacturers start to make cheap, easy to mount, USB2-only connectors for low cost low speed devices, but it sure would be nice.Quote from: Howardlong on March 05, 2019, 05:50:32 pmSo one case of user error, and two cases of electrical damage. I don't think the connector or the interface standard is to blame here. Possibly inadequate ESD protection on the USB2 lines, or a malfunctioning device or cable in the latter two cases.

author: tooki
author_rank: Super Contributor
timestamp: March 05, 2019, 09:23:09 pm
content: Quote from: ajb on March 05, 2019, 07:03:19 pmWell, in all fairness, the recent hubbub about "USB 3.2 Gen 2×2" and whatnot is totally unfounded, insofar as those are the technical names of the transfer modes, which are of interest to hardware developers only, and aren't intended to be put on products. The "marketing names" for consumers are fairly straightforward:SuperSpeed USB,SuperSpeed USB 10Gbps, andSuperSpeed USB 20Gbps.Quote from: ajb on March 05, 2019, 07:03:19 pmYes, backwards compatibility can be a bad thing, if it's not actually compatible! And that's precisely the problem with USB-C: things LOOK compatible but AREN'T. With USB type-A and B connectors, if it mates, it should work (assuming driver support). With USB-C, this is no longer the case.So yes, there's a significant argument for keying connectors to prevent incompatible connections. But I wasn't talking about speeds — thosearecompatible. The incompatible features are Thunderbolt vs USB signaling, charging support, etc.Quote from: ajb on March 05, 2019, 07:03:19 pmExactly. It's why I asked. None of this indicates to me that the connectors are fragile, which is what the original post claims. There are many enduring complaints about USB-C, but connector robustness isn't one of them.

author: Halcyon
author_rank: Unknown
timestamp: March 05, 2019, 11:12:08 pm
content: Quote from: Howardlong on March 05, 2019, 01:04:44 pmAbsolutely. I've lost count on how many Apple Macbooks I've come across with one or more failed connectors.I have a Dell Latitude 7490 laptop I used primarily for work (and apart from it's several design flaws surrounding heat dissipation) I feel as though the USB C docking station connector will snap one day.The cable to the dock is far too rigid. They've clearly beefed up strain relief on the cable/connector itself, but the weakest part is now the socket inside the laptop.

author: Red Squirrel
author_rank: Super Contributor
timestamp: March 05, 2019, 11:19:30 pm
content: USB standard has always been a huge mess. They even rename standards at time, they're doing that with USB 3.x, it's ridiculous.One thing I find annoying about USB C is that it's such a tiny connector, to me they should have made a larger version and a smaller version. The larger version would be for computer stuff, like mice, keyboards etc and then the smaller one would be for mobile. The bigger ones will tend to be stronger and just overall better for computer stuff.I try not to wrap my head around too much of the specifics of the standards, that's how I stay sane.

author: tooki
author_rank: Super Contributor
timestamp: March 06, 2019, 03:36:09 am
content: Quote from: Red Squirrel on March 05, 2019, 11:19:30 pmNah, I think that would have been a terrible idea. There's no real advantage to a larger connector. Your assumption that a larger one would be more robust is certainlynota safe assumption — look at, for example, DisplayPort. The mini-DP connector has provenfarmore robust than the larger one, due to how the large DP connectors tend to be attached to the wire. And a larger connector means a larger connector body to bump into.Furthermore, why would you think that small devices wouldn't need their connectors to bemorerobust? They're more likely to be used in situations where the connectors get bumped while in use. And with the vast majority of computers sold nowadays being laptops, where space is at a premium, those would want to use the small connectors anyway.Ultimately, manufacturers need to be designing robust connector assemblies and mounts, so that it's not the solder joints taking the force of a bump. Apple's approach of using the unibody housing to be integral strain relief is a good start, but they can still do better.

author: rsjsouza
author_rank: Super Contributor
timestamp: March 06, 2019, 04:17:49 am
content: I feel this pain everyday. I use a Dell Precision 5510 with a docking station that supports 4k60p of my Viewsonic monitor. However, to my surprise, I could only get 4k30p and it took me quite a while to figure out the docking supports the 4k60p but only if you don't plug anything else to it, let it be an extra monitor, Ethernet or a single stupid USB pendrive.Yes, Dell sells a more amped docking station that supports the full resolution, but that is mentioned in small print of each dock's manual. It gets to a ridiculous extreme of downloading a series of manuals (one for each possible candidate), consulting FAQs, etc. I haven't had this much work with a somewhat "pedestrian" solution since I was scrounging the internet to extract the minute nanosecond of the DDR memory tied to my Athlon 64 3500.

author: Halcyon
author_rank: Unknown
timestamp: March 06, 2019, 05:15:32 am
content: Quote from: rsjsouza on March 06, 2019, 04:17:49 amDell has a track record of this. I bought a Dell touchscreen and soundbar. The soundbar was advertised as being compatible with Dell monitors (via the included mount). You click on the "Compatibility" tab and no mention of any model numbers for monitors... until you download and read the manual, it only supports monitors of particular model series.I spent 30 minutes trying to work out how to get the damn mount to attach before realising the speaker isn't compatible with the monitor I had. Itlookslike it's going to fit and attach (the mount is spring loaded to accompany different width stands) but then doesn't.Never again will I buy a Dell product (with the exception of their business range of UltraSharp monitors).

author: Howardlong
author_rank: Super Contributor
timestamp: March 06, 2019, 09:55:58 am
content: Quote from: tooki on March 05, 2019, 09:23:09 pmRegarding the "user error" which I freely admit, the point is that I didn't force it in, I was fumbling around the side of the laptop. The design of receptacle, with the inner tongue with contacts, is physically fragile. Had the receptacle been a USB A, or micro A, or Thunderbolt 1 or 2, the problem wouldn't have arisen.As a further data point, an ITX motherboard I have which sports a USB Type C potentially could have easily suffered damage when the I/O shield fingers chose the "wrong route" when I placed the board in the case. Thankfully I was paying attention, and avoided any impact, but I am absolutely certain others will not have noticed this until it's too late.I'll add the following key point that I didn't mention earlier: the USB Type C receptacle is much more likely to suffer damage than the plug. If a cable assembly breaks that is in general going to be a far cheaper and easier thing to replace compared to a board assembly or board rework.And. of course, who am I to disagree with my neighbour Brian May? ;-)Quote

author: Howardlong
author_rank: Super Contributor
timestamp: March 06, 2019, 10:33:55 am
content: Quote from: rsjsouza on March 06, 2019, 04:17:49 amFWIW, I must have a dozen or so USB-C & Thunderbolt docks of one sort or another, but my single port non-TB solution to the 4k60p problem coexisting with other devices is this:https://www.cablematters.com/pc-899-126-usb-c-to-4k-60hz-displayport-multiport-adapter.aspxwhich allows for 100MBbps Eth and a pair of USB 2.0 ports. Judging from its 100Mbps limit, I assume the Ethernet is USB 2.0 based.(Of course it says "Thunderbolt 3 Port Compatible", but it's not a Thunderbolt 3 solution!)

author: David Hess
author_rank: Super Contributor
timestamp: March 06, 2019, 12:50:02 pm
content: Quote from: Howardlong on March 05, 2019, 01:04:44 pmThe first USB PD ASICs I saw advertised in the trade magazines had DRM for the power delivery advertised as a major feature. There were all kinds of different schemes before this but USB PD natively included it.

author: OwO
author_rank: Super Contributor
timestamp: March 06, 2019, 01:22:06 pm
content: I've had a burnt USB-C connector on a phone. One day I just plugged it in and it burned for no apparent reason. Probably some pins were offset too much and shorted. Never had this kind of crap with micro or mini USB.The reversible cable and power direction is an anti-feature. If I plug in a power bank to a phone I want the power bank to charge the phone and not the other way around, but I hear of this happening all the time. Even if you can get the negotiation to work properly I still think reversible power flow direction is a STUPID idea. I don't want the possibility of something draining power from the charging port of my laptop.

author: Halcyon
author_rank: Unknown
timestamp: March 06, 2019, 08:52:13 pm
content: Quote from: OwO on March 06, 2019, 01:22:06 pmI don't see it as any different to having a load on any version of USB port to power the connected device. Sure, previously the output current has been relatively low on most devices. I see more positives than negatives, for example: I no longer need to source external power to use an external spinning rust hard disk drive.I'm sure on most devices (such as on Android phones), there is the option to disable power delivery via USB. I know my Samsung Galaxy S8 has.