Now let me talk bout how USB communicates with host(pc's etc)
USB has what you call endpoints,interfaces,configurations which are used to communicate with usb core.

The most basic form of USB communication is through something called an endpoint.
A USB endpoint can carry data in only one direction, either from the host computer to the device (called an OUT endpoint) or from the device to the host computer
(called an IN endpoint). Endpoints can be thought of as unidirectional pipes.
There are 4 types of endpoints which can be configured

1)CONTROL
Control endpoints are used to allow access to different parts of the USB device.
They are commonly used for configuring the device, retrieving information from/of device etc.These endpoints are usually small in size. Every USB device has a control endpoint called “endpoint 0”

2)INTERRUPT
Interrupt endpoints transfer small amounts of data at a fixed rate every time the
USB host asks the device for data. These endpoints are the primary transport
method for USB keyboards and mice.

3)BULK
Bulk endpoints transfer large amounts of data. These endpoints are usually
much larger (they can hold more characters at once)These endpoints are common on printers, storage and network devices.

4)ISOCHRONOUS
Isochronous endpoints also transfer large amounts of data, but the data is not
always guaranteed to make it through. These endpoints are used in devices that
can handle loss of data, and rely more on keepinga constant stream of data
flowing. Real-time data collections, such as audio and video devices, almost
always use these endpoints.

Brief overview

USB(Universal serial bus)as the everyone knows has taken world by storm.It is a specification to establish communication between devices and a host controller ie PC and it went on to become most used interface in PC history.

Lately with introduction of USB3.0(super speed version)in late 2009 curiosity level has increased manifold.It has speed advantages w.r.t USB2.0 which we use nwadays.Following are some of the advancements from USB2.0 which has been incoporated in/going to be incoporated in USB3.0:

1)Increase the speed of USB to 5 Gb/s (~10 times faster than USB 2.0)
2)Provide effective bandwidth of approximately 400MB/s
3)Backward compatible to USB 2.0 at protocol level
4)Mostly same connector footprint as USB 2.0
5)Lower power consumption
6)More power over cable (2.5W to 4.5W)
7)Lower software overhead

USB 3.0 is driven by consumer demand for faster transfer from flash
devices storing music, pictures and video.
I haven't gone into the details of working of USB n other details regarding how it communicates etc etc which you can expect to see in next posts.

Getting Started

Hi

This being my first ever post/blog i have joined the bandwagon finally.!Looking forward to many more interesting insights/views from my end about USB