USB Explained

Universal Serial Bus is a newer kind of port that allows
communication between your computer and an attached device.

What's a Port?

A port is an interface for attaching external devices to a computer. The original IBM personal computers came with two ports -- a serial port and a parallel port. Typically, devices such as modems were attached to the serial port and devices such as printers connected to the parallel port. Another type of port called the SCSI port became a mainstay in the Mac world, but never caught on in a big way in the PC world.

A port not only connects an external device, but it also controls the transfer rate, or the rate at which data can be transferred between the computer and the attached device. This is where the USB port excels. On the average, USB allows data to travel at 10 times the speed of the normal parallel port. It is also faster than a serial port. This means that a USB printer or scanner can operate faster than a printer or scanner that hooks up to the parallel port. The average serial port transfer rate is 150 KBPS; the parallel port is a 1.2 MBPS. The USB port transfers data is between 1.5 MBPS and 12 MBPS depending on the type of device that is connected.

Each of these different types of ports is uniquely different. While a computer can have several different types of ports built into it, each port can be used to connect only it's own distinctive type of peripheral. If a device is made with a parallel port connection, it can only be hooked up to a parallel port. If a device is make with a USB connection, it can only be hooked up to a USB port.

What does the USB port look like at the back of your computer?

What does the male end look like?

Stackable & Swappable USB has other advantages as well

Although I can't imagine why anyone would want to, you can attach up to 127 devices to one USB port. USB ports are self-powered, so you can say good-bye to those big chunky power blocks. However, if you attach more than a few devices you will need to add a self-powered hub, which is a small mechanism that provides extra power to the attached devices. The idea behind USB is that the devices will be daisy-chained together. The USB device that you purchase should have another built-in USB port so you can hook other devices to it. Many of the USB monitors that I've seen come with three USB ports for attaching other devices. USB keyboards also have several built-in USB ports where you can hook up other devices. For instance, your mouse might connect to your keyboard, your keyboard to your monitor and your monitor to your computer. This eliminates the mess of power cables that often accompany a computer system.

USB devices are hot swappable

You can plug in and remove any USB devices without turning the computer on and off. This is a great feature for those of us who want to only purchase one peripheral to use on two or more computers.

USB Devices

You can plug just about anything into a USB port: keyboards, cameras, mice, joy sticks, modems, zip drives, floppy drives, printers, and scanners. You can even purchase USB speakers to produce great digital sound on your computer. As you read this, more and more USB devices are becoming available. Eventually serial and parallel ports will disappear on new computers. So if you are adding a new device to your computer, you really should consider a USB device. By the way, USB devices do not cost any more than other peripherals.

Do you already have a USB port?

Many computers that were manufactured in the past two years have USB ports. Look at the back or side of your computer. Most of the ports have rows of small pins or pinholes where new peripherals can be plugged in. The USB port looks slightly different. It is a small thin opening. It has no obvious pins or pinholes. It is often, but not always marked "USB". Many computers have two USB ports. See the port above.

Adding a USB Port

If your computer doesn't have a USB port, you can add one by buying an inexpensive adapter card that fits into a PCI slot in your computer. If you have a notebook computer, you can purchase a USB port that fits into the card slot. However, you should be aware that USB devices can use a lot of your computer's power. This is not a problem if you have a desktop computer or are using your notebook computer with an A/C power cord. However, if you plan to run your portable computer on its batteries, a USB device can be a power drain on the batteries. Remember that if you decide to add a USB port you will want to upgrade to Windows 98 to make your USB experience a pleasant one.