Universal Serial Bus By Clint Johnston

1. What is USB? USB or Universal Serial Bus is specification to establish communication between devices and a host controller( PC ). Most common type of USB connection.

2. Who made USB?? The Genius who created USB is Ajay Bhatt while working for Intel. He was and still is employed by Intel. This lovely fellow.

USB is intended to replace many varieties of serial and parallel ports. USB can connect computer peripherals such as mice, keyboards, digital cameras, printers, personal media players, flash drives, and external hard drives. For many of those devices, USB has become the standard connection method. USB was designed for personal computers, but it has become commonplace on other devices such as smartphones, PDAs and video game consoles, and as a power cord. As of 2008, there are about 2 billion USB devices sold per year, and approximately 6 billion total sold to date. What are some of the uses of USB?

Some History on USB. USB began development in 1994 by a group of seven companies: Compaq, DEC, IBM, Intel, Microsoft, NEC and Nortel. The USB 1.0 specification was introduced in January The original USB 1.0 specification had a data transfer rate of just 12 Mbit/s. The first widely used version of USB was 1.1, which was released in September had a transfer speed of 12 Mbit/s. The USB 2.0 specification was released in April 2000 and was standardized by the USB-IF at the end of USB has a higher data transfer rate, with the resulting specification achieving 480 Mbit/s, a fortyfold increase over 12 Mbit/s for the original USB 1.0.

A closer look at some of the peripherals that use USB USB Mass Storage Device

USB extension cord Range of different connection types male Micro B male Mini B (8-pin) male Mini B (5-pin) female standard A male standard A male standard B From left to right One thing to note on the extension cord is that it has a maximum length of 5m. USB1.1 (3m), USB 2(5m per cord up to 30m using Cords and USB hubs).

2 Main Different types of USB connectors. Standard type A Is a flattened rectangle. This plug is frequently seen on cables that are permanently attached to a device, such as one connecting a keyboard or mouse to the computer. USB connections eventually wear out as the connection loosens through repeated plugging and unplugging. The lifetime of a USB-A male connector is approximately 1,500 connect/disconnect cycles. Standard type B Has a square shape with bevelled exterior, and is generally seen on a device that uses a removable cable, e.g. a printer. A Type B plug delivers power in addition to carrying data. On some devices, the Type B receptacle has no data connections, being used solely for accepting power from the upstream device.

USB Mini and Micro connectors The Mini-A and Mini-B plugs are roughly 3 by 7 mm, while the Micro plugs are roughly half the thickness. Mini-USB is often used by digital camcorders. The Micro-USB connector was announced January 4, As of February 2009, many devices still use Mini plugs, but the newer Micro connectors are being widely adopted. Micro-USB is being used as the standard connector for data and power on mobile devices. These include various types of battery chargers, allowing Micro-USB to be the single external cable link needed by some devices. As of January 30, 2009 Micro-USB has been accepted as the standard charging port across most of the world. Worldwide conversion to the new cellphone charging standard is expected to be completed between 2010 to In addition, on 22 October 2009 the International Telecommunication Union (ITU) announced that it had embraced micro-USB as the Universal Charger Solution its "energy-efficient one-charger-fits-all new mobile phone solution.

Break Down of USB speeds A low-speed rate of 1.5 Mbit/s is defined by USB 1.0. This is deemed the full-bandwidth operation. (The bare minimum speed data will travel) The full-speed rate of 12 Mbit/s is the basic USB data rate defined by USB 1.1. All USB hubs support full-bandwidth. A high-speed (USB 2.0) rate of 480 Mbit/s. All hi-speed devices are capable of falling back to full-bandwidth operation if necessary; they are backward compatible. Connectors are identical.

A Look into the Future A Super Speed (USB 3.0) rate of 4800 Mbit/s. The written USB 3.0 specs was released by Intel and partners in August The first USB 3 controller chips were sampled by NEC May 2009 and products using the 3.0 specs arrived beginning in January USB 3.0 connectors are generally backwards compatible. That’s all folks.