1 February 2007, Comments: 17

We try to cover in this USB 2.0 FAQ the basic aspects for those who are not too familiar with the serial bus technology. This FAQ is limited to just a few questions so you won’t be overwhelmed by the length of the entire FAQ. And for those who are interested in latest USB standards, we also have FAQs on Wireless USB and USB 3.0. Here’s also an interesting TV ads showing featuring Ajay Bhatt, the co-inventor of USB.

What is USB 2.0?

Finalized in 2001, Universal Serial Bus (USB) 2.0 is a complete overhaul of the Universal Serial Bus input/output bus protocol which allows much higher speeds than the older USB 1.1 standard did. The goal of the new serial bus is to broaden the range of external peripherals that can be used on a computer. A hard drive can easily hit the USB 1.1 bottleneck whereas it now becomes more ‘usable’ under USB 2.0 conditions. For those people who found us via search engines, USB 2.0 should neither be called ‘USB2’ nor ‘USB 2’.

What happened to USB 1.1?

USB 1.1 allowed a maximum transfer rate of 12Mbits/second. It is now obsolete, but both of its speeds (1.5Mbps & 12Mbps) are being adopted into USB 2.0, and they are now called Original USB officially. Though some manufacturers label their products Full-Speed USB. Note that this seems a bit deceptive as it’s easy to mistake Full-Speed for Hi-Speed. You won’t be fooled from now on as you are now aware that Full Speed USB is only 12Mbits/second where Hi-Speed USB mode is capable of a much faster 480Mbits/second.

Traditionally, USB mice and keyboards only need 1.5Mbps to function; exceptions are gaming mice and keyboards that require 12Mbps. These higher-end gaming products send way more location feeds thru USB; hence, more bandwidth is required. Generally, the performance levels (1.5Mbps & 12Mbps) are grouped under ‘Original USB’ by the USB Promoter Group.

The logo shown on the right is authorized by the same organization to the vendors for use on their products should they pass the compliance tests.

How do I know if my PC has USB 2.0?

You can identify whether your PC has Hi-Speed USB or not relatively easy. Open Device Manager and expand the Universal Serial Bus section. There should be an “Enhanced” USB host controller present.

Windows 98 systems may use a different name because Hi-Speed USB drivers in these operating systems are not provided directly from Microsoft (Windows ME, 2000 and XP get their drivers through Windows Update).

These drivers are provided by the manufacturer and may carry the maker’s name (i.e. ADS, Belkin, IOGear, Siig, etc.). There should also be two “standard” version USB host controllers present as well. They are embedded in the USB chip which routes the differing USB speeds accordingly without user intervention.

There are currently 7 manufacturers of the Hi-Speed USB host silicon themselves:

  • ALi (Acer Labs)
  • Intel
  • NEC
  • SiS
  • VIA
  • nVidia (shows as “Standard” controller)
  • Philips

Any other brand name that appears in Device Manager would likely be an add-in Hi-Speed USB PCI card. The makers above do not make add-in cards, but they do make the chips that are used in them.

Do you need USB 2.0?

Almost every conceivable peripheral has USB 2.0 version ranging from a surround gaming headset, portable hard drive to even USB video card. So, even if you buy a all-in-one HP multimedia PC with all the gizmos, you’ll still need something USB.

Should you own a laptop, you may like to know that USB is also your ticket out of the proprietary world. It used to be that docking stations must all match that exact notebook model due to the proprietary connection. Now, you can just plug in a USB notebook dock, and you’ll get a USB video adapter, hub, 7.1 surround audio, serial converters, Ethernet plus a notebook holder.

How do I know I plug in a Hi-Speed USB device?

The simplest way is to look for a Certified Hi-Speed USB logo on the retail packaging or on the product itself. The logo is exactly as shown on the right; it tells you what you are plugging into your USB port has passed the Hi-Speed compliance tests, meaning the product can enter Hi-speed USB mode if your system supports it.

USBInfo & SiSoftware Sandra can also report USB speed status. If you are certain you got some Hi-Speed USB ports, you can download the aforementioned utilities to check out your devices’ USB speed (anything above 12Mbps is surely Hi-Speed USB).

How does USB 2.0 handle today’s applications?

Many have asked us how USB 2.0 or Hi-Speed USB mode specifically can handle today’s ever-changing applications, particularly in the multimedia field. The original USB has an inherent problem to meeting the bandwidth requirement of the current CD burners and hard drives. If memory serves us well, USB CD burners hit the bottleneck at 8x or 1.2MByte/s, and USB hard drives couldn’t exceed a pitifully 1MByte/s.

When USB 2.0 introduced Hi-Speed USB mode, it boosted bandwidth to 480Mbit/s or 60Mbyte/s. The forty-fold jump from the original USB’s 12Mbit/s has paved way for a number of improved devices. As we’ve seen, there is a dual SDTV tuner, each of the tuners consumes 8Mbit/s after the MPEG-2 conversion. For DVB-T/B USB tuners, each HDTV stream requires 55Mbit/s or 11% of what USB 2.0 offers. Technically, Certified Wireless USB can handle several HDTV channels simultaneously. For a few USB Video Class-enabled camcorders available, DV mandates 3.6Mbyte/s (or 43Mbit/s) for the linear video stream; it fills up a hard drive at a rate of 13GB per hour.

As for a lot of USB storage, burning a DVD-R at its fastest rate or 16x takes up 21MByte/s or 169Mbit/s. That translates to 35% of overall USB 2.0 speed. Hard drives, however, demand a huge amount of bandwidth that USB 2.0 cannot meet; we’ve seen a USB 2.0 hard drive has sustained 36 to 40MBbyte/s in the absolute best scenario. USB flash drives have also reached 33MBytes/s, but there seem to be some limitations in the NAND itself so you shouldn’t expect their speeds to skyrocket in the next year or two. For most consumers, there shouldn’t be a problem with running out of bandwidth.

How do USB 2.0 and 1.1 work together?

You may have heard that USB 2.0 is backward-compatible with USB 1.0/1.1 (Full-Speed USB). While that’s true, USB 1.1 is also forward-compatible with USB 2.0. Whenever a system has USB 2.0 ports, you’ll find the “Enhanced” USB controller in Device Manager, but you will also find two other USB controllers.

These two maintain backward compatibility with USB 1.1 devices. Each USB 2.0 host actually has 3 chips on board. The USB controller routes signals to the correct controller chip depending on how a device is recognized. Where a device is physically plugged in has no bearing on how it is routed. All ports on a USB 2.0 motherboard can host any USB device at all as long as the system and devices are healthy.

The vast majority of USB 2.0 devices will work on older PCs and Macs. None should flat-out fail unless there are other issues with the system. Hi-Speed USB devices will revert to Full-Speed operation when connected this way. Understand that Hi-Speed is at least ten times faster than Full-Speed in actual operation, so the speed difference is quite noticeable – unless you have never experienced Hi-Speed, of course. When it comes to USB hub compatibility between USB 2.0 and USB 1.1, here are some facts:

  • A powered hub is always preferable to unpowered.
  • USB hub ports are not as capable or flexible as real PC ports so it’s best not to expect the world of them.
  • USB 1.1 (obsolete) hubs will work fine on USB 2.0 ports, but they cannot utilize USB 2.0 capabilities. They will default to slower speeds.
  • Hi-Speed and Full/Low-Speed USB devices can coexist nicely on USB 2.0 hubs. Connecting such a hub to a USB 2.0 port is recommended.
  • USB 2.0 hubs can be used on older USB 1.1 computers.
  • Although it is said that you can cascade up to 4 hubs, problems may start to arise after two hubs, it’s best to minimize hub usage if possible.
  • Many USB devices don’t work well on hubs. Cameras, scanners and especially USB drives are known to have problems with hub connectivity.
  • Remember that active USB extensions are really just one-port hubs.

As you can see, there are very few issues (if any) to be concerned about when mixing USB types. If the system and devices are healthy, it should be a no-brainer to connect any USB device – provided that you follow the manufacturer’s instructions.

How does a USB hub slow down devices?

A USB hub has to re-calculate the time left before the next sof (end of the uframe); the small extra delay added by the hardware hub could make the transaction not handled as fast as a device directly connected to the host. If several devices are connected on the USB hub and working in parallel (for example, a webcam + a USB flash drive + a mouse), then the USB bandwidth is shared among the device usage.

USB Duplicators By Nexcopy
Nexcopy manufactures a variety of PC-based and standalone USB duplicator solutions.

PC based systems support advanced USB functions such as write protection, CD-ROM partition and multi-partition creation, while standalone systems are ultra-fast, high speed USB copiers duplicating gigabytes of data quickly and accurately.

17 responses on “USB 2.0, Hi-Speed USB FAQ

  1. Can you tell me please, what is the best USB 2.0 or 3.0?

  2. cemaginnis says:

    I think I fully understand the capabilities, differences, similarities, and functions of USB 2.0 vs. USB 3.0 and Flash Drives vs. SD/Micro SD cards.

    Here is my question. If I put my MicroSD UHS-1 card in a UHS-1 reader and plug it into a USB 3.0 port, will I get significantly faster speeds than if I plug it into a USB 2.0 port?

    I cannot find any information on this. Thanks.

    • Steven Gordon says:

      I’m not sure. If it has a USB 3.0 plug, blue and 9 pins, probably, just as long as the card supports the increase in transfer speed

  3. Darr247 says:

    When I click the “How fast is USB 2.0?” link, it takes me to a page about USB 3.0.

  4. Susan Hjort Weeden says:

    THIS is driving me NUTS!!

    When I had to Clean Install Win7 (bc2uz I had WinXP!)…I lost my Enhanced USB2 ports!! Now all I get is the d#&* msg. This Device Can Work Faster Plugged Into A USB2 Port…etc!! I KNW…I USED 2 have them!!

    WHAT can I DO 2 GET ‘EM BACK??

    • Darr247 says:

      Find the Win7 “chipset” driver for your motherboard… also called ‘4-in-1’ or ‘All-in-one’ drivers by some manufacturers.

  5. Angel At Large says:

    Really helpful! Cheers.

  6. Othelo says:

    I think most of the CPUs nowadays are already equipped with USB 2.0 so you don’t necessarily need to buy a separate expansion card. [video depot, video, videos, depot.wen.ru]

  7. loadnabox says:

    While devices are backwards compatible, you generally cannot upgrade a USB device or port. This is due to the need (as described above) for three chips in a USB 2.0 system. One is used to identify the data packet and route it to oe of two more chips,the next takes the USB 2.0 data and the third takes the data for USB 1.1 devices. This means that a USB 1.1 system wouldn’t have enough chips to properly handle a USB 2.0 connection.

    USB 3.0 uses a completely different plug with additional wires so there’s no way to modify the existing plug to the new standard.

    You have several options: If it is a desktop system, and you haven’t used up all your expansion slots, you can buy a USB2.0 or 3.0 expansion card relatively cheap from Amazon ($5-20)

    If you’re running a laptop, you MIGHT have a PCMCIA or ExpressCard slot. If you don’t know take it to a Best Buy and ask, they can identify which you might have (if any) at a glance (a 30 second visual inspection will tell the technician all he needs to know without powering it up) Depending on which type of these slots you have (and what version of USB you want) you can get an expansion card for $8-20

    If you have a laptop and no PCMCIA/ExpressCard slot you’re unfortunately out of luck.

  8. Chaplain Jack says:

    Were can I buy a 75ft HI-Speed USB 2.0
    cable I am using it on a CAD U37 Microphone.

  9. Akeem Arizona Kizart says:

    I have a 1.1 usb computer, (even though its only a year old!! 🙁 ) and I need to know if there is anyway that I can change it to a 2.0 usb. I am a musician, and I just bought an interface that is only 2.0 compatible.

    • Joe Taylor says:

      If it has a PCI socket on the motherboard you can buy a cheap 2 or 4 port USB 2.0 host from best buy or just about any other place that sells computer hardware and accessories

  10. Dean You Lee says:

    I have Ubisoft Battletag, which runs on USB 2.0. Lasertag blasters are connected via a radio antenna (“a ubiconnect”) to a PC via the USB 2.0 port. I am not sure if the antenna is full speed or high speed.

    We experience latency issues when more than 16 players log onto the system – could this be addressed by ensuring the antenna is running at high speed?

    Is is possible to upgrade a 2.0 device to usb 3.0?

    If so, do you think that this will resolve latency issues?

  11. usbhispeed says:

    really helpful suggestions, thanks !
    usb gia re – usb3.0

  12. Shushanto Bose says:

    Does one USB 2.0 cable fit all devices that use USB 2.0? I mean is it universal for the device or just universal for the PC? I want to use a cable that is meant for an Epson printer for my Cowon MP3 player. The device-jack looks the same.