Difference Between USB 1.1 and USB 2.0 ?

**Aapti** · 17-02-2009

Hello

I Have An Computer Whenever i Try to Use my New USB Flash Drive , Windows Prompt me a messages that these device can perform faster, then i came to know that i have a USB 1.1 Port and the My Flash drive is UsB 2.0 Device, But Dont Know the difference Between the usb 1.1 and Usb 2.0 I have read that the USB 2.0 and 40 times faster than USB 1.1 port,please Verify and Clarify my Doubt Thank you and goodbye.

**The Edge** · 17-02-2009

USB 1.0 can operate at 1.5 Megabits per second (Mbps).USB 1.1 allowed a maximum transfer rate of 12Mbits/second. USB mice and keyboards need only 1.5Mbits/s to function. That performance level is also named 'USB'.USB 2.0 has a raw data rate at 480Mbps, and it is rated 40 times faster than its predecessor interface, USB 1.1, which tops at 12Mbps. Originally, USB 2.0 was intended to go only as fast as 240Mbps, but then, USB 2.0 Promoter Group increased the speed to 480Mbps in October 1999.You can use USB device with USB 1.0, USB 1.1 and USB 2.0 as long as your PC or laptop has USB ports, but USB 2.0 device transfer data at 480 Mbps on systems with USB 2.0 support only.

**RoninBlade** · 17-02-2009

USB 2.0 is backward compatible with 1.1 (I am not sure 1.0 made it to the consumer market...). This means any 2.0 device will work with the older 1.1 spec devices. If there are any 1.0 devices, I would guess they are supported too. The newer/faster device will automatically talk at the lower speed to accomodate the slower hardware.

I saw a document that said 1.0 did not support extension cables or simple in-monitor style hubs.

The USB 1.1 spec. has a data rate of 12 Megabits per second. USB 2.0 runs at 480 Megabits per second. You probably don't actually get these speeds because of bus overhead and sharing (if you have more than one device on the bus).

So if you have a USB 1.1 port on your computer it will talk to 2.0 devices, but may not be fast enough to use them if they require the higer data rate of 2.0.

If you have a 2.0 port on your computer, any USB device ought to work (provided there are device drivers for your OS).

**Fabian** · 17-02-2009

USB 2.0 (Hi-speed USB) increases the data transfer rate from 12 Mbps (Megabits per second) of USB1.1 up to 480 Mbps.USB 2.0 is both forward and backward compatible with USB 1.1. USB specification version 2.0 is the next-generation peripheral connection for personal computers. It is intended as an upgrade for USB 1.1. Not only the new standard provides additional bandwidth for multimedia and storage applications but also offers Plug-and-Play capability and full backward compatibility for legacy USB devices.

**deoWo** · 17-02-2009

USB 1.0

USB 1.0: Released in January 1996.
Specified data rates of 1.5 Mbit/s (Low-Speed) and 12 Mbit/s (Full-Speed). Does not allow for extension cables or pass-through monitors (due to timing and power limitations). Few such devices actually made it to market.
USB 1.1: Released in September 1998.
Fixed problems identified in 1.0, mostly relating to hubs. Earliest revision to be widely adopted.

USB 2.0

USB 2.0: Released in April 2000.
Added higher maximum speed of 480 Mbit/s (now called Hi-Speed). Further modifications to the USB specification have been done via Engineering Change Notices (ECN). The most important of these ECNs are included into the USB 2.0 specification package available from USB.org:
Mini-B Connector ECN: Released in October 2000.
Specifications for Mini-B plug and receptacle. These should not be confused with Micro-B plug and receptacle.
Errata as of December 2000: Released in December 2000.
Pull-up/Pull-down Resistors ECN: Released in May 2002.
Errata as of May 2002: Released in May 2002.
Interface Associations ECN: Released in May 2003.
New standard descriptor was added that allows multiple interfaces to be associated with a single device function.
Rounded Chamfer ECN: Released in October 2003.
A recommended, compatible change to Mini-B plugs that results in longer lasting connectors.
Unicode ECN: Released in February 2005.
This ECN specifies that strings are encoded using UTF-16LE. USB 2.0 did specify that Unicode is to be used but it did not specify the encoding.
Inter-Chip USB Supplement: Released in March 2006.
On-The-Go Supplement 1.3: Released in December 2006.
USB On-The-Go makes it possible for two USB devices to communicate with each other without requiring a separate USB host. In practice, one of the USB devices acts as a host for the other device.
Battery Charging Specification 1.0: Released in March 2007.
Adds support for dedicated chargers (power supplies with USB connectors), host chargers (USB hosts that can act as chargers) and the No Dead Battery provision which allows devices to temporarily draw 100 mA current after they have been attached. If a USB device is connected to dedicated charger, maximum current drawn by the device may be as high as 1.8A. (Note that this document is not distributed with USB 2.0 specification package.)
Micro-USB Cables and Connectors Specification 1.01: Released in April 2007.
Link Power Management Addendum ECN: Released in July 2007.
This adds a new power state between enabled and suspended states. Device in this state is not required to reduce its power consumption. However, switching between enabled and sleep states is much faster than switching between enabled and suspended states, which allows devices to sleep while idle.
High-Speed Inter-Chip USB Electrical Specification Revision 1.0: Released in September 2007.