Superior Speed, Performance Fuel Adoption OF USB 2.0


In every corner of the IT and consumer markets, USB 2.0 and its progeny for mobile devices,USB On The Go (OTG),are quickly taking over as the de facto USB standard for enabling the speedy exchange of data and communication among an ever-growing list of devices.

As PCs, peripherals, consumer electronics and mobile devices embrace the new standard, market-research firm In-Stat/MDR predicts that the number of USB 2.0-enabled devices will grow to 863 million in 2007 from 375 million in 2002.

Fueling the race to embrace USB 2.0 are its superior speed and performance. The original USB,USB 1.1, which was introduced in 1995,offers transmission speeds of up to 12 Mbps. In contrast, USB 2.0, introduced in 1999, offers a 40-times increase in speed,to up to 480 Mbps,while remaining backward-compatible with USB 1.1 devices.

The higher speed of USB 2.0 has brought connectivity to an array of devices,such as external hard drives, CD/DVD drives and scanners,that require fast connections to take full advantage of their performance and were unable to connect via USB 1.1 because of its speed limitations.

Supporters of USB 2.0 first predicted that it would dominate the IT peripherals market in 2000. USB 2.0 was integrated into core logic chipsets in mid-2002, which means that 100 percent of desktop computers shipped by the end of 2003 should include USB 2.0, said Brian O'Rourke, a senior analyst at In-Stat/MDR.

At the same time, however, mice, keyboards and other devices with lower speed requirements are still embracing USB 1.1 because of its lower cost.

USB 2.0 was also made available to mobile devices late last year when USB OTG was finalized. USB OTG transmits at the same rate as USB 2.0 and, by using smaller connectors, enables peer-to-peer connections between devices such as cellular phones, handheld computers, printers and cameras, as well as connecting such devices to PCs.

While standard-size USB 2.0 works under a master-slave protocol, in which the host computer provides commands and electrical power to the peripheral, USB OTG works under a 'dual-role peripheral' protocol, in which either device can act as the host or peripheral and no electrical power is exchanged. USB OTG is starting to appear on mobile chipsets currently in production, and should appear on mobile phones and other devices in early 2004.

Inhabiting the same space as USB 2.0 is FireWire, also known as IEEE 1394. The two standards have experienced an uneasy coexistence, sometimes fighting for the same market share and at other times existing as complementary standards. USB 2.0 has a higher speed,480 Mbps vs. FireWire's 400 Mbps,and FireWire has higher electricity demands than USB OTG. Those demands make FireWire prohibitive for mobile devices, although a low-power version is under development.

FireWire also is a peer-to-peer connection and can transmit over longer cables, which has helped fuel its use in the consumer market. While USB 2.0 has settled in as the standard of choice for IT peripherals, FireWire has found a home among products that require high speed and bandwidth, such as consumer audiovisual devices, digital cameras and high-quality video streams used in the digital video industry.

However, there are signs that the current detente between USB 2.0 and FireWire is coming to an end. USB 2.0 is pushing to consolidate its monopoly among peripherals and is simultaneously pushing into the consumer space.

"USB's top theoretical speed is up in the neighborhood of [that of IEEE] 1394 and is ubiquitous in the PC market, whereas 1394 isn't, and so it will begin to push 1394 out of the PC market, as well as out of devices that connect to the PC, such as consumer devices," O'Rourke said.

Although consumer electronics devices have been slower to adopt USB 2.0 than IT peripherals because they aren't tied as closely to PCs and often don't have the same speed requirements, In-Stat/MDR predicts that most eventually will move over to the new standard.

Meanwhile, Apple Computer, which is fighting to maintain FireWire's position, doesn't support USB 2.0 on its computers, although it did support USB 1.1. The company recently launched a salvo in the data-transfer race with the development of an enhanced version of FireWire. The new version, FireWire 800, can transfer data up to 800 Mbps,nearly twice the rate of USB 2.0,but is currently available only on the PowerBook G4.