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USB 2.0: The Express Bus Arrives


Until about four years ago, the only way to attach a peripheral to a PC was either to install a card in one of the expansion slots or to plug the device into the serial or parallel port.

The advent of Universal Serial Bus ports made it a lot easier to connect scanners, printers, keyboards and digital cameras.

Unlike serial and parallel ports, USB allows a virtually limitless number of devices to connect to a PC.

Optional hubs allow users to add as many as 127 devices to a single PC. Most PCs have only one parallel port and one or two serial ports.

The limit of USB, though, is speed.

The original USB specification of 12 megabits per second isn't really fast enough to run DVD players, CD recorders or even video cameras at full throttle.

USB 2.0 is a new protocol likely to become a standard by the end of this year. At 480 Mbps, USB 2.0 is 40 times faster than the USB 1.1 ports on today's machines.

Most users who transfer huge amounts of data between peripherals and their PCs rely on a FireWire, also known as 1394, port.

At 400 Mbps, FireWire is almost as fast as USB 2.0. But it's not standard equipment on most PCs. Apple, which invented FireWire, offers it on all new Macs. PC makers typically install FireWire only on higher-end consumer systems.

Users could always add a FireWire port to a desktop or notebook PC, but the fact that something can be added doesn't mean that people will.

In the history of personal computing, the only devices that achieved widespread popularity have been those that connect via a standard interface.

That's why USB devices have done so well.

Once Intel, Apple and all the PC makers standardized the technology, it was only a matter of time before virtually all the peripheral makers adopted it as well.

The industry is moving over to USB 2.0, but it won't happen immediately. Compaq, for example, plans to include USB 2.0 as standard equipment on desktop systems beginning in March.

USB 2.0's big advantage over FireWire is that it is backward compatible with USB 1.1. That means new USB 2.0 ports and hubs also will accept USB 1.1 devices.

It also means that peripherals designed for USB 2.0 also can connect to the older-style ports, albeit at a slower speed.

I tested this by installing a $70 Belkin 5 Port USB 2.0 PCI Card in my desktop PC.

Once the card was installed, I connected a $200 USB 2.0- and 1.1-compatible Maxtor 3000LE 40-gigabyte external drive.

In 49 seconds, I copied a 50-MB directory from my internal drive to the Maxtor.

I then plugged that same drive into my machine's original USB 1.1 port.

The transfer took 4 minutes and 6 seconds.

True, USB 2.0 wasn't 40 times faster, but that's because the drive itself became the bottleneck rather than the connection between the drive and the PC.

I plugged the same drive into the USB 1.1 port on my laptop, and it worked just fine.

An external USB 2.0 drive is a great backup device because if anything should happen to your PC, you can easily move it to any other PC--even if it has an older USB port.

Backward compatibility is a win for the industry and consumers.

For vendors, it means being able to build one device that they can sell to people with older or newer systems and, by providing special drivers, to Mac users as well.

For consumers, it means not having to worry about obsolescence. Even if without one of the newer ports, a USB 2.0 device bought now will work on existing machines.

And even better on the next one.


Technology reports by Lawrence J. Magid can be heard between 2 and 3 p.m. weekdays on the KNX-AM (1070) Technology Hour. He can be reached at larry.magid@latimes .com.

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