Talk:Universal Serial Bus/Archive 4

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Contents

First sentence garbled in "Proprietary connectors and formats" section

Sentence is either run-on or mis-punctuated. Don't know enough re XBox to correct it. Peter Delmonte 17:52, 7 October 2007 (UTC)

Are cables for USB 1 the same as cables for USB 2?

Are cables for USB 1 the same as cables for USB 2? I have searched the web for an hour and can not find a clear answer. I suspect they are physically the same, but may be tested differently? If someone knows the answers, it could save millions of cables from ending up in the dump.

I see ads saying a cable is "USB 2.0 High Speed Certified" but what does it mean? —Preceding unsigned comment added by 69.228.83.182 (talk) 02:59, 11 October 2007 (UTC)

Cables made before USB 2.0 did not have controlled differential impedance. If impedance of the twisted pair in the cable deviates significantly from 90 Ohms, High-Speed USB devices will suffer from signal reflections, and distorted USB packets would cause excessive data corruption and corresponding attempts to recover. There are also certain elevated requirements for levels of transmission losses, and for wire gages, to deliver power to bus-powered devices, including lower contact resistance. "USB 2.0 High Speed Certified" means that the cable meets all these requirements.Alexei123 04:48, 25 October 2007 (UTC)
I'm not positive but my understanding is that if a cable was properly made to USB 1.1 specs it should be ok for the high speed mode introduced in 2.0. Unfortunately as with everything there are many cables out there that weren't made to the proper specs. Plugwash 12:42, 18 October 2007 (UTC)
Since coaxial cables at those frequencies are treated as waveguides, they need to be specially engineered for the higher speed. True, a hi-quality USB 1.1 cable designed to cover the full range of frequencies that appear at the maximum rate for USB 1.1 (11 Mbps) and allowing for some headroom, should accomodate USB 2.0 Hi-Speed (12 Mbps) but not Full-speed, which is 480 Mbps. The very least you will get a lot of errors and retries with such a cable. EpiVictor 12:46, 18 October 2007 (UTC)

Fair use rationale for Image:Usbovercurrent.png

Image:Usbovercurrent.png is being used on this article. I notice the image page specifies that the image is being used under fair use but there is no explanation or rationale as to why its use in this Wikipedia article constitutes fair use. In addition to the boilerplate fair use template, you must also write out on the image description page a specific explanation or rationale for why using this image in each article is consistent with fair use.

Please go to the image description page and edit it to include a fair use rationale. Using one of the templates at Wikipedia:Fair use rationale guideline is an easy way to insure that your image is in compliance with Wikipedia policy, but remember that you must complete the template. Do not simply insert a blank template on an image page.

If there is other fair use media, consider checking that you have specified the fair use rationale on the other images used on this page. Note that any fair use images uploaded after 4 May, 2006, and lacking such an explanation will be deleted one week after they have been uploaded, as described on criteria for speedy deletion. If you have any questions please ask them at the Media copyright questions page. Thank you.

BetacommandBot (talk) 20:52, 26 November 2007 (UTC)

USB 4.0

How is it that I'm seeing hardware coming out which claims to have USB 4 connectors, but I can't find any real data about USB 4?

This is what I've found and have no way of verifying it's accuracy:

Leaked draft for USB 4.0 specification

1. One symmetrical, fully bi-sexual hardware interface, no male/female connectors, no fumbling to find the right direction for the plug, no unnecessary adapters.
2. Hybrid fiber optic / electric interface, fiber for data at speeds exceeding 1GB/s, can be updated indefinitely via DSP, electric for legacy data and power to supply energy dependent devices.
3. 12 Volts, 3200 mA max distributed power via the bus. This is enough to power to run standard 3.5" disk drives, CD/DVD drives, scanners, printers, and other small devices that USB does not support.
4. Backwards compatible with Ethernet, and all 8P8C / RJ45 variations- requires adapter.
5. Intelligent connectivity, full data/power link is not established until hardware determines the appropriate device settings and requirements.
6. Small enough for use with micro devices like flash memory, MP3 Players and mobile phones yet pragmatic enough to endure in adverse environments.
7. No DRM / Copy Protection junk. Additionally the standard is entirely open source and does not require a costly license or any other idiotic nonsense to utilize.

So... does anybody have any more information about this? —Preceding unsigned comment added by 67.190.44.253 (talk) 03:55, 4 December 2007 (UTC)

IIRC, USB 3 isn't even available yet to the general public. How could devices be available that claim to be USB 4? Sounds like a typo. Brielle (talk) 21:56, 28 January 2008 (UTC)
That sounds like a Slashdot wanker wishlist, not a proposal. SchmuckyTheCat (talk)
I think this rumor came from someone misinterpreting what they were reading. Originally, it was probably either satire or someone's discussion on what would be a good idea. Some of those seem like they might be good ideas, but it's highly unlikely that there's any sort of work started on a USB 4 draft by people who will have an impact on it, other than perhaps idle design discussions. I'd like to point out that much of it isn't coherent. #7 sounds like uninformed jibber-jabber; "open source" and "DRM / Copy Protection junk" have little or nothing to do with USB. Also, #4 doesn't make sense; while adding compatibility with Ethernet would be cool, it isn't called back-compatiblilty, since Ethernet is a parallel technology. Also, USB and Ethernet are are wildly incompatible from the topology's perspective; you could mate Ethernet with Firewire, but not with USB, at least not without a complex interface device that already exists; nor is it "compatible" if you need an adaptor (I already have a USB to Ethernet "adaptor"). I'm not sure what #2 means. From reading the main article, it seems like #5 is already implemented in USB 2. Obviously, #6 is already implemented as well (many of us already own USB flash memory readers). -- 67.132.216.172 (talk) 23:00, 23 February 2008 (UTC)

Fix rationale behind "max latency limits max length"?

Ok, so the section under cables states that the maximum length of a USB cable is 5 meters because of latency issues. Where it makes a mistake though, is saying those issues are caused by the per-meter latency specification.

Regardless of the physical constraints, all the specification constraint does is force the maximum length to be at least 5 meters. That is, no cable less than or equal to 5 meters in length whose per-meter latency meets the 5.2 ns standard could possibly fail the 26 ns per cable standard.

If I (hypothetically) have a copper wire whose latency is 1 ns per meter ("less that 5.2 ns per meter"), it could be 26 meters in length while still being in compliance with the specifications. A 1 picosecond per meter latency could be 26000 meters in length, etc.

The article should be re-worded to say the 5 meter limit is imposed by the physical constraints of the wire combined with the per-cable specification. The actual physical limit of information is approximately 3.34 ns per meter, based on the speed of light. 26 ns / ~3.34 ns ~= 7.79, so unless there's some overhead not mentioned, a "perfect" cable would be safe to beyond 7.79 meters. Edit, forgot to sign: fosley 131.50.151.8 (talk) 21:47, 11 December 2007 (UTC)

Upgrading: Picture USB_types_2.JPG

  • First post to discussion forum, so please forgive any errors.

I have altered USB_types_2.jpg to include 1cm tick marks on the 5cm scale at the bottom of the pic. If this is considered beneficial, please see http://www.gentwood.com/USB_types_2.jpg to retrieve it and put it in the original's place. (I do not know how to replace a pic and would not do so in any case until verifying you agree.) Thx. Gloucks (talk) 00:51, 16 December 2007 (UTC)


another image or an adjusted caption would be necessary, but i don't know where to get one or what the actual type of this plug on the outer left actually is.

cheers, mike —Preceding unsigned comment added by [[User:{{{1}}}|{{{1}}}]] ([[User talk:{{{1}}}|talk]] • [[Special:Contributions/{{{1}}}|contribs]])

At least Fujifilm FinePix F40fd camera has such a connector. 85.156.235.161 (talk) 23:07, 21 January 2008 (UTC)

Add a list of problems

Please add a list of problems that the user might encounter: having to unplug and replug a device because it has "died", etc. Jidanni (talk) 02:10, 20 December 2007 (UTC)

Wikipedia is not a troubleshooting site or a manual. Groink (talk) 05:16, 20 December 2007 (UTC)

Video tapes

Can USB be used to transport video from tapes, or only digital? —Preceding unsigned comment added by SantanaHomerunner (talk • contribs) 18:34, 28 December 2007 (UTC)

In short, yes you can. There are dozens of devices on the market that will allow "analog" video like VHS, Betamax, etc. to be captured on a PC via USB. Best resource for further research would be videohelp.com - try http://forum.videohelp.com/topic341813.html for starters. Groink (talk) 18:55, 28 December 2007 (UTC)

revert on Overcurrent

An editor removed a section describing Apple's use of higher than 500ma on ports as being out of spec with the edit summary "not out of spec." The spec is section 7.2.1.2, overcurrent, and says "The preset value cannot exceed 5.0A" and any compliance test (required for logo certification, see USB.org document "USB Compliance Checklist, Systems") will attempt to trigger this condition and fail the port. SchmuckyTheCat (talk)

Mac Book Air USB port

The Apple Documentation states that this port is completely within specifications 500 mA at 5V. Accordingly I reverted the unsourced fact that the port is proprietary:

MacBook Air Computers (January 2008)
The MacBook Air computer introduced in January 2008, based on the Intel Core 2 Duo, has multiple internal USB controllers built into the South Bridge.
The external USB port supports 500 mA at 5 V for 2.5 W.
The external USB port complies with the Universal Serial Bus Specification 2.0. High-speed USB devices are accessed via the Enhanced Host Controller Interface (EHCI) and full-speed and low-speed devices are accessed via the Universal Host Controller Interface (UHCI).
A high-powered Apple keyboard can be attached directly to the external port, and software will enable one of its downstream ports to supply 500 mA of power. The external port also supports the External MacBook Air SuperDrive when it is directly attached.

[1] -- KelleyCook (talk) 15:09, 5 February 2008 (UTC)

"First" USB device

I found mention of the Toshiba "InTouch" control panel, which is claimed to be the "first" USB device in this press release (warning - popup ads):

http://findarticles.com/p/articles/mi_m0EIN/is_1996_Sept_19/ai_18690920

Is there any truth to that claim? The InTouch control panels were part of Toshiba's Infinia desktop PCs. —Preceding unsigned comment added by 24.107.203.128 (talk) 00:22, 9 February 2008 (UTC)

Maybe. They weren't very great at being compliant and even though all they did was HID type stuff they weren't HIDs. There were plenty of devices (keyboards, mice, hubs) that were closer to both bus and HID compliance that were in test labs at the same time. They may have been the first device actually seen in major US retail stores. SchmuckyTheCat (talk)

USB B Pin out incorrect?

I viewed a few websites that had the pin out on the USB B connector different. So I went to the spec and it looks like wikipedia's image is incorrect. I think the USB B connector pin out is mirrored. Pin 1 is top right, Pin 2 is top left, Pin 3 is bottom left and Pin 4 is bottom right. http://www.usb.org/developers/docs/usb_20_092407.zip (9.7MB spec) - see figure 6.8 on page 96 of USB_20.pdf. I am going with the spec for my hardware so will find out soon on the protype!203.89.189.117 (talk) 21:25, 11 March 2008 (UTC)

Remember with any connector the pinout on the face of the plug is the mirror image of the face of the socket. If you assume the wikipedia image is the face of a plug it is consistant with the spec. If you assume the wikipedia image is the face of a socket then it is wrong. The image on wikipedia looks more like a plug than a socket to me so on that basis it is consistant with the spec (which gives the face of the socket) Plugwash (talk) 19:58, 13 March 2008 (UTC)

Image Request

 It is requested that an image of USB micro B plug be included in this article to improve its quality, if possible.

(Can we get permission to use Mobileburn's Picture: Mini vs Micro USB) -- User:76.209.28.72 16:54, 4 June 2007 (UTC)

Size limitations

This article states: "Unlike most other connector standards, the USB spec also defines limits to the size of a connecting device in the area around its plug."

I've been unable to find this in the specification document. It only seems to specify connectors for cables. I've also found contradictory advice in the USB-IF developers forum ("maximum/minimum physical dimension of a USB dongle"). Does anyone know where this information came from?

DFU

From openmoko

USB Device Firmware Upgrade (DFU) is an official USB device class specification of the USB Implementers Forum.

It specifies a vendor and device independent way of updating the firmware of a USB device. The idea is to have only one vendor-independent firmware update tool as part of the operating system, which can then (given a particular firmware image) be downloaded into the device.

In addition to firmware download, it also specifies firmware upload, i.e. loading the currently installed device firmware to the USB Host.

Larytet

Thanks!

A useful and informative encyclopedia article! Many thanks to the authors and editors.

Speed is the wrong term

A speed is measured in meters per second (or whichever inches per millennium). A rate is measured in cubic meters per second or in units per second (or whichever...). All occurrences of speed should be replaced by rate in this article. A Pirard 12:02, 30 October 2007 (UTC)

Here's one word for you: anal. Have you ever sat in a LAN party and have two techies talk tech and use the word "rate" in a sentence (other than how they rate the only female in the group?) EVERYONE uses the word speed when describing how fast something is - from broadband Internet connectivity to PC bus performance. In everyday spoken language, speed and rate are virtually interchangeable. If you're trying to correct the rest of the world, this is not the way to go about it. Groink 20:12, 2 November 2007 (UTC)
One link for you: WP:CIVIL. Read it. -- trlkly 09:39, 14 April 2008 (UTC)

Missing Connector Types