Chapter 14: Using USB and FireWire Interfaces

Overview

If you can do it without moving a lot of furniture around, take a look at the back of your computer. You can see a bunch of mismatched connectors that all require different kinds of cables. There's probably a serial data port or two and a printer socket, plus assorted other connectors for the keyboard, the mouse, the monitor, the speakers, the network, and maybe a telephone line. Except for the keyboard and mouse sockets, every one of those connectors was originally designed for some other purpose and tacked onto personal computers when somebody decided that their systems needed to connect to something or other.

But it didn't stop there. Still other devices came along that needed a way to connect to a computer. These included external storage devices such as Zip drives and tape drives, and new kinds of input sources such as scanners and digital cameras. Some of these products used the existing serial or parallel port connectors and others came with their own special expansion cards that added yet another type of connector to the mixture.

This all happened gradually, as each generation of computers added a few more connection types, but by the mid-1990s, some of the biggest players in the personal computer business (Microsoft, Intel, Hewlett-Packard, Compaq, and NEC among them) began to recognize that enough was enough. The solution to the problem of too many connectors was the Universal Serial Bus (USB), which could use the same connector for many purposes. The original USB specification had a maximum data transfer speed of 12 Mbps. A few years later, the USB 2.0 standard increased the maximum to 480 Mbps.

At about the same time, Apple Computer extended its FireWire high-speed serial data transfer method from internal hard drives to external peripheral devices. The Institute of Electrical and Electronics Engineers (IEEE) adopted the FireWire specification as a standard for both Macintosh and Windows computers, which it called IEEE 1394. Sony was the first of many camcorder makers to use IEEE 1394 as a way to transfer video to computer (they called it i.LINK). The maximum data transfer speed through a 1394 interface is 400 Mbps, but even faster FireWire 800 (800 Mbps) interfaces are beginning to appear on some new computers and motherboards.

Note 

Strictly speaking, FireWire is Apple's trademark for its use of the IEEE 1394 specification; any use of that standard that does not involve either a computer or a peripheral device made by Apple should be called an IEEE 1394, or a 1394 connection, or device, or port, or whatever. In practice, this is widely ignored, and the two names are used as if they are interchangeable.

From a user's perspective, the greatest benefit of both USB and IEEE 1394 is that they allow you to simply plug a cable into a socket-any socket-on the front or back of the computer and expect the computer to automatically recognize the gadget on the other end of the cable. If you're using a new device for the first time, Windows might tell you to load some device driver software, but after that, it's all automatic. And the hot-swap feature means that you can connect and disconnect your camera or telephone or portable flash drive (or anything else) without the need to shut down the computer first.

More than ten years after the first USB ports appeared on motherboards and assembled computers, they still haven't completely replaced all those other inputs and outputs, but the industry is definitely moving in that direction. FireWire connections are less common, but they have become a standard for many multimedia devices and applications. By the time you're ready to replace the computer that's on your desk today, it's entirely possible that the new one will use USB and IEEE 1394 connectors for everything except the digital cable for your video display.

In this chapter, you can learn how the USB and FireWire standards work, and how to use them in Windows-based computers.