Talk:Universal Serial Bus

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[edit] Over-rated durability

"The encasing sheath and the tough molded plug body mean that a connector can be dropped, stepped upon, even crushed or struck, all without damage" Well, the encasing might easily be bent by stepping on it, requiring the user to bend it back in order to connect it again. Sure, the "important" thing (the connector) isn't broken, but if the encasing is bent you won't be able to insert it. So, I think that the durability of USB contacts isn't as good as what the wiki page now says it is. Ran4 (talk) 19:04, 7 May 2008 (UTC)

I agree - USB reliability is overrated in the article; the mini USB on my Wrist PDA now fails intermittently after 3 year, 1-2 inserts per day.

Another agreement. The Mini plug sucks, it works itself loose until the tight fit is loose, and the contacts don't mate. —Preceding unsigned comment added by Ligart (talk • contribs) 04:52, 28 May 2008 (UTC)

[edit] PlusPower / Powered USB

These two specifications seem to be the same. PlusPower is PoweredUSB 0.8e and Powered USB contains version 0.8f of the same specification. So, these sections under Power should probably be merged, links and additional information moved to Powered_USB page and if there is some real differences between those two, it can be discussed under Powered USB page. —Preceding unsigned comment added by 82.181.111.137 (talk) 18:23, August 29, 2007 (UTC) And while talking about cleaning the article, enhanced mini-B. motorola and HTC connectors probably are of little interest to most people since there are dozens of other non-standard USB connectors. At least the connectors don't belong under device classes. Perhaps separate page for non-standard USB features is required? Nonstandard_usb perhaps? All weird devices and connectors could be listed there without having to worry that readers of the main article get confused with all the variations... —Preceding unsigned comment added by 82.181.111.137 (talk) 18:33, August 29, 2007 (UTC)

[edit] Minor Edits

Hi, I removed the point that USB connectors are 'cheap to manufacutre' since this can almost be said about anything that is mass-manufactured - I somehow doubt that there is any reason why USB could be considered to be significantly cheaper than any other type of connector. Also, I removed "......." that was at the end of a sentence. Silica-gel (talk) 09:15, 13 May 2008 (UTC)

If this was sourced, it should be returned to the article. USB plugs and headers are significantly cheaper (even in mass production) than legacy ports they replaced: RS-232, IEEE1284, DB-9, etc. OEMs look at savings of a penny, even fractions of a penny, cost differentials.
If it is not sourced, it should not matter that it was removed. Someone can add it later with a ref. SchmuckyTheCat (talk)

[edit] Mystery micro plug

The mystery plug, on a cable for my Pentax K10D
The mystery plug, on a cable for my Pentax K10D

(continuing the above section, on the small 8-pin plug which is apparently misadentified as "micro-B" in this image)

I agree that this plug is not a standard micro-B plug, which is about 7×1.8mm and has 5 contacts, as described precisely in the "USB Cables and Connectors Class Document".

I have one of these "mystery plugs" on a cable for my Pentax K10D camera and don't really know what to call it. Its dimensions are approximately 4.75×1.8mm, smaller than standard micro-B. And it has positions for 8 contacts, not the 5 of micro connectors. I have seen it on several cameras, where it is usually used to provide both USB and composite video via the same receptacle on the camera (hence the extra 3 pins).

This connector/cable seems to be used by many different camera brands, including at least:

  • Pentax, Konica-Minolta, Olympus [1]
  • Nikon [2]
  • Fujifilm [3]
  • Panasonic [4]
  • HP [5]
  • Kodak [6]

I have seen it referred to with several names:

  • "Mini USB 8P"
  • "Mini B 8 Pin"
  • "Mini 8 Pin"
  • "8 pin flat"

Is this thing standardized or not?? There appears to be a huge amount of confusion around it... Can anyone explain what it is supposed to be called, or reference any documents that describe it??? ǝɹʎℲxoɯ (contrib) 20:59, 14 May 2008 (UTC)

I don't know whether it could be called standardized or not, but I can tell you what it is. It's a "USB multi-connector" that's very popular on midrange DSLRs, including pins for USB, video output, and often a remote shutter release. The function of the port varies depending on which cable is attached. As far as I know there's no agreement between manufacturers as to pin assignment, but it's not unreasonable that they would have a common physical spec.

Andrew Rodland (talk) 09:42, 9 June 2008 (UTC)

[edit] Slim USB

There seems to be an influx of "slim" or "flat" USB connectors. Where are these mentioned? What are the specs? (See here)

Coolhandscot (talk) 18:54, 15 May 2008 (UTC)

This doesn't appear to be anything new. It is just a standard USB connector without the metal jacket that hugs around the USB connector. Groink (talk) 20:47, 15 May 2008 (UTC)

[edit] USB Cable Extension

Can we have a subsection for USB Cable Extension? The article needs more practical information. For example, the maximum length of 25-30 feet is not possible in practice, due to operating system and device limitations, not mentioned in the article. Active hubs "theoretically" increase range, but in reality, your OS and the device you are connecting will reject more than 2 hubs. 1 active extensions seems to always work, but in OSX 10.4 you can have just one, and in Windows XP you can sometimes use 2 active USB extensions. So in reality you can extent just 32 feet. —Preceding unsigned comment added by 76.120.102.109 (talk) 08:35, 18 May 2008 (UTC)

WP:BOLD. Come up with verifiable sources, and then write the section. Groink (talk) 08:50, 18 May 2008 (UTC)

I have a 12 m (cca. 40 feet) USB 1.1 extension (three 4 m USB A extension cables plugged together, without active components) between a computer and a printer (data exchange only, both obviously have seperate power units) - using it without a problem. I didn't actually realize there is a length limitation until reading this. —Preceding unsigned comment added by 212.201.44.249 (talk) 16:39, 20 May 2008 (UTC)

"Active Extensions" are bus-powered hubs. The specification allows one layer of a bus-powered hub in a topology. Extending with just extender cables isn't allowed at all in the specification. There are plenty of commercial range-extending products (including cat5 as physical layer, ethernet as a MAC layer, and wireless) that are also outside the specification.
Any kind of jury-rigged solution (commercial or not) that is outside the specification has no reason to be discussed in an encyclopedia article unless it is so common (like the usage on gaming consoles) that leaving it out is a disservice to readers. SchmuckyTheCat (talk)
Can you point out (with a URL or page link) where in the specification it only allows one layer of bus powered hub? I don't understand why the spec should care since a hub is a hub whether bus powered or externally powered.
The only issue that I can fathom has to do with current draw, and a single-port bus-powered hub is considerably different in operation from a multi-port bus-powered hub since it only has to carry its own weight for current draw and pass the rest of the capacity down the chain. Does the spec make a distinction between single-and-multi port bus-powered layered hubs?
I'm of the opinion that the single-port hub extenders didn't exist as a concept when the spec was originally created so it may not be officially supported only because the spec writers didn't think of that application at the time of writing the spec. DMahalko (talk) 11:10, 21 May 2008 (UTC)
I do not have time right now to go dig in the spec. The statement "a hub is a hub..." is incorrect also. A BP hub is only required to provide 100ma per port, an SP hub 500ma. Most BP hubs will gang the 500ma (minus the ma used by the hub itself) from the bus to a single port if the device requests it, but it is not required. Regardless of why, there is only one allowed layer of BP hubs.
Additionally, I've never come across a active extension cable that did not claim to be a 4 port self-powered hub. Nobody sends these things for compliance testing either, so they aren't logo certified. Since they claim to be self-powered, the OS (any OS) has no reason to force compliance with the bus-power spec and you can daisy chain them until you run out of power or maximum SP hub depth. That isn't to say that making a single port bus-powered hub that IS in compliance with the rest of the spec isn't possible, but, AFAIK, they don't exist.
It isn't our job as encyclopedia writers to contemplate hypotheticals, second-guess the USB-IF, describe work-arounds or provide trouble-shooting. There are plenty of other internet sources for that, quality YMMV. SchmuckyTheCat (talk)

[edit] Older HIDs

The article section on Human Interface Devices states that these can use PS/2-to-USB adapters without internal logic since these devices have logic to do either PS/2 or USB. This may be true for newer PS/2 devices, but older seem not to have such capability. While investigating the conversion of an IBM Model M keyboard to USB (cheaper than finding a new PS/2 cable for the same), I discovered that many have had problems getting a straight PS/2-USB adapter to work. There are devices described as PS/2-USB converters (Clickykeyboards web site on PS/2 to USB converters) that apparently contain some sort of logic (just a class 03 id perhaps?).

I don't know whether its worth adding something about this to the article. --Michael Daly (talk) 21:39, 27 May 2008 (UTC)

As I read the article, it is discussing bundled adapters. You buy a new USB mouse, and find a PS/2 adapter in the box, or vice versa. Converting equipment made before USB was even thought of is going to take more work.
It is useful to read that section however. It is older thank Wikipedia's reference fetish and probably needs to be sourced and re-written at some point. SchmuckyTheCat (talk)