USB lets your PC get connected easily

July 20, 1998|By Mike Himowitz

Take a look at the back of your computer some time. It can be pretty intimidating. I count no fewer than 13 cables protruding from mine - and naturally they're all tangled up in a clotted mess behind the machine. Half the time, I can't remember which one goes where, and I plugged every one of them in myself.

Now I'll admit I'm a bit more wired than the average user. But can certainly sympathize with the computer owner who wrote to say that he was confused by advertisements for gadgets that are supposed to plug into various ports on the back of his machine.

"I was looking at video cameras," he said, "and I found a model I liked that came in two different versions - one that plugs into your printer port and one for the USB port (whatever that is). Which one is better? If I use the one that plugs into the printer port, can I still use my printer? And how do I even know if I have a USB?"

Good questions all. And in order to make an intelligent buying decision, it pays to know a little bit about those mysterious plugs and receptacles on the back of your PC.

By itself, your computer is no more than an expensive paperweight. It must have some way to communicate with printers, modems, scanners, cameras, monitors, disk drives and - ultimately - with you.

The ports on the back of your PC are paths to various circuits in your computer that control all these gadgets. They come in various shapes and use different types of cables and connectors because they handle data in different ways.

The most overworked port on most systems is the parallel port, which was once known as the printer port before people started plugging other gadgets into it. You can tell a parallel port because it has 25 holes in two rows.

The parallel port gets its name from the way it handles data. When you send information to a printer, it travels in bytes, which consist of eight digital ones and zeros (known in the trade as bits). The parallel port uses eight wires (one to handle each bit), so that the entire byte arrives at its destination at the same time. This is fast and efficient, but because electrons are unruly, the bits get out of synch over long distances. So parallel port communications are generally limited to 15 feet - even less with some devices.

While it was originally designed primarily for one-way communications, a parallel port can pass data to and from a computer. In the last four or five years, computer makers have enhanced this capability, and now parallel ports are also used to hook up high-capacity removable drives (such as Iomega's ZIP), as well as scanners and video cameras that once required

separate controller boards.

The problem is that most PCs have only one parallel port. To be sure, removable drives and scanners have pass-through capability - you plug the drive into your parallel port and your printer into a port on the drive. The hardware figures out when you're communicating with which device.

But some of today's advanced printers - which use two-way communications to tell you when there's a paper jam or your ink cartridge is running low - don't like sharing a parallel port. Some parallel port video cameras won't share at all - to use the camera, you have to unplug the printer. This isn't a fatal flaw if you can reach your cables without doing a contortionist act, but it's annoying. In any case, there's certainly no way you can hook up a removable drive, scanner, camera and printer to the same parallel port and expect any of them to work properly.

Enter the Universal Serial Bus. This circuitry, which began to appear on computers about two years ago, was designed as a one-size-fits-all connection between your computer and external devices.

With one or two high-speed USB ports (flat receptacles about a half an inch long and an eighth of an inch high), your computer should be able to control monitors, scanners, drives, cameras, keyboards and just about anything else you want to plug in.

USB devices are designed for "daisy chaining," which means that you can plug a USB monitor into your computer, and then plug a printer into a port on the monitor, and then a scanner into a port on your printer, and so on down the line. You'll also be able to buy a relatively inexpensive USB "hub," a box that plugs into your computer's USB port and allows you to attach a half dozen other USB devices - a much neater solution than a daisy chain.

With Apple moving to the USB on its new iMac computer, the technology makes it possible for Macs and PCs to use the same equipment.

Unfortunately, USB technology has been tough for manufacturers to master, and we're just starting to see USB printers, monitors, cameras and scanners on store shelves.

There's also a software issue. Your computer has to know how to access a USB device, and Windows 95 required modifications to make the USB port work. Even then, it wasn't very reliable. Windows 98 is the first version of the operating system to have USB support built in.

After I installed Windows 98, I tried both parallel and USB versions of the Connextix QuickCam, a popular PC video camera. I found very little difference in speed or image quality, both of which should have been better with the USB model.

Even so, if you have a Windows 98 computer, or you're thinking of upgrading, USB peripherals are the wave of the future. They're certainly worth considering.

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Pub Date: 7/20/98

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