A truly universal connection

Ajay Bhatt, inventor of the USB

Winners of the European Inventor Award 2013 in the category Non-European countries

Ajay V. Bhatt, Bala Sudarshan Cadambi, Jeff Morriss, Shaun Knoll, Shelagh Callahan, inventors of the USB

The Universal Serial Bus (USB) is an innovation that truly lives up to its description. The convenient USB plug and its protocol system have long become a standard in the computer industry. Today, there are billions of USB-enabled electronic devices throughout the world, in everything from webcams to cell phones and memory sticks.

Working as team lead on a group that created and patented USB technology, Intel computer expert Ajay V. Bhatt helped greatly simplify the way we interact with computers and usher in one of the most revolutionary advances in computing since the development of the silicon chip.

The time before convenient connections

In 1990, while installing a new printer on his wife's computer, Ajay V. Bhatt was confronted with an all-too-common frustration: connecting new peripheral devices - such as printers, scanners and modems - was a time-consuming headache.

Back then, computer users had to negotiate a maze of competing plug designs on the back of their desktops, install new drivers and often open up the machine to add new computer cards. This was followed by a tedious process of trial and error, which required repeated rebooting of the computer system and fine-tuning until everything worked properly.

If this situation was frustrating for Bhatt, who worked at the forefront of computer development at chip giant Intel, he could only imagine how difficult it was for average users. Fortunately, Bhatt saw an opportunity to greatly simplify the process. His innovative solution soon became one of the key technologies that helped shape modern computing.

"Global unit sales of USB devices are expected to surpass 7 billion annually by 2015."

A creative outlet

Growing up as the only technically-minded child in a family of liberal-arts professionals, Bhatt had long been the go-to person to fix radios, televisions and circuit breakers. His interest in electronics eventually led him to leave his native India to study at City University in New York, where he helped develop video technology used aboard the Columbia Space Shuttle.

Of course, creating a convenient way to connect new devices to a computer required a very different approach than designing space-shuttle electronics. For inspiration Bhatt turned to the common electrical wall outlet. Would it be possible to design a system that worked in a similar way and allowed users to simply plug devices into their computer and have them work automatically? With this question, the seeds for USB technology were sown.

Communication breakdown

The source of the problems associated with installing new devices could be traced to crossed lines of communication within the computer. Computers worked in much the same fashion as a poorly designed multinational telephone switchboard, where each peripheral device had to dial in to the ‘operator' - the computer's circuit board - and each device spoke its own ‘language'.

To understand this chatter, the operator needed translation help: a specific driver for each device that was able to decode its language and ensure that all information either sent or requested was handled properly. Each driver had to be installed separately by the user.  

In addition, every time a new peripheral device was added, it became increasingly difficult for the computer to keep separate the various ‘conversations' and prioritise between competing tasks. Often, some of the functions of various devices would simply stop working - or the computer would crash unexpectedly.

Bhatt's solution was to radically streamline communication within the computer. Instead of letting each device communicate through its own native language and talk whenever it needed to, he combined the different signals into one central line of communication that was sent directly to the computer's operating system.

One plug to rule them all

The USB protocol system's hub, which Bhatt designed, acts like a ‘translator' between the various devices and the computer no longer receives conflicting requests. Significantly more advanced than the earlier setup, it also allows the user to connect a much larger number of separate devices to a computer at one time than had been previously possible: up to 127, in theory.

Working alongside a team of computer and communications specialists at Intel, Bhatt was able to develop the first fully functioning form of this architecture in 1994. Intel began filing for a patent shortly thereafter. The original unwieldy name, ‘hierarchical serial bus assembly', was later changed to Universal Serial Bus (USB) to reflect the universal way it connected with computer devices. Intel partnered with several computer companies - including Microsoft, Compaq, Digital, Northern Telecom, NEC and IBM - to implement USB into the computer market.

Initial market penetration was slow because USB required a redesign of the Microsoft WindowsTM software platform that wasn't available until 1998. In the meantime, Apple computers launched its iMac, the first mass-produced USB-enabled computer. In this bestselling computer's wake, thousands of USB products were created, serving almost any function imaginable.

A boon for the users and the industry

Today, painstaking installations are a thing of the past, and USB technology allows devices to work across different software platforms. Users can plug and unplug devices whenever they want, and they don't need to notify the computer or reboot their system before they use a device for the first time. In addition, USB supplies electricity to run and recharge mobile phones and music players.

The technology is also a great asset for hardware and software developers and saves countless hours in product development because devices no longer have to be checked and re-checked for possible conflicts. Developers need only follow USB standards, and end-users are virtually guaranteed trouble-free connections.

Global success

Attaching a price tag to the USB technology spearheaded by Bhatt is nearly impossible; the innovation is not marketed and sold as a product but has been used for more than a decade as an industry standard. As of 2011, 7 billion USB-equipped devices have been shipped worldwide, and 3.5 billion of these devices were delivered in 2010 alone. Industry research firm In-Stat expects global unit sales of USB devices to surpass 7 billion annually by 2015.  

The success of the USB standard has far exceeded what Bhatt originally envisioned. It even included a television advertisement honouring his achievement - with the suave Indian actor Sunil Narkar playing the part of Bhatt.

Despite the attention, Bhatt has stayed true to his original goal of enhancing and simplifying how users interact with their computers. In addition to USB technology, Bhatt has at least 31 distinct major patents in various stages of filing.

He was named one of ‘The most influential global Indians' and was a finalist for The Light of India Award in 2012 honouring his contributions to the advancement of science and technology. Bhatt's most recent technological contribution plays a major role in the creation of a lightweight, energy-efficient laptop computer capable of running an entire day on a single charge. The new laptop is scheduled to be unveiled in early 2013.    

Ajay V. Bhatt's source of inspiration: the common electrical wall socket.

How it works

When a USB-enabled peripheral device is attached to a computer, it is assigned a number called an ‘address' by the USB hub, the translator which sends information back and forth between devices and the computer's main circuit board. The USB hub also determines which kind of device has been plugged in and what type of data-transfer connections (called stream pipes) this device should share with the computer.

Devices such as keyboards and mice need to send small amounts of information quickly and are given special ‘interrupt-transfer' stream pipes that give them priority in the system. Other devices are assigned stream pipes that allow them either to send large chunks of information at a slower rate but with great accuracy (bulk transfer) or smaller amounts of data at a faster rate, but without error handling (isochronous transfer).

Devices might have a collection of different stream pipes, depending on the specific function they are performing at the time. This differentiation allows the computer to handle the various requests for information efficiently, but also to ensure that critical functions remain intact.

The USB hub cycles through each of the devices countless times a second and sends packages of information back and forth on the stream pipes. When bandwidth is limited, the hub removes congestion by restricting the frequency at which low-priority bulk transfer stream pipes (and, if necessary, even isochronous stream pipes) can transfer information.

USB data-transfer rates have increased significantly in two successive generations following the original version developed by Bhatt. Originally able to transmit 12 Megabits per second, the most recent USB 3.0 version is 3,500 times faster.

USB, standards and ‘patent pools'

Intel Corporation was granted a patent on USB technology in 1997, but the protocol system was created in conjunction with six other companies. The technology has become a standard in the industry. However, from both a legal and a business perspective, patents and industry standards can be problematic.

Companies need to fully disclose all relevant patent information before trying to implement proposed industry standards. It might also be expensive to protect and maintain these types of patents and their proprietary nature might hinder wide-spread use.

One solution to these problems is to create a "patent pool" - something used by companies associated with the USB standard. All holders of essential patents relating to USB technology - either the first or subsequent USB versions - have combined their patents into one pool called the USB Implementers Forum.

This organisation allows other participating companies to license USB patents under RAND (Reasonable and Non-Discriminatory) terms without having to pay royalties. Implementers, who use the USB standard, are free to create products that support the standard without fear of lawsuits from the patent holders.

"The technology is also a great asset for hardware and software developers and saves countless hours in product development."

Quick Navigation