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What is USB – The Universal Serial Bus

If you have a look at the back of a typical PC, you’ll find a serious number of differently shaped connectors – and if you’re lucky, they may even be labelled so that you know what to connect to each of them!

In brief, there are one kind of connector for printers, two or more versions of connectors for serial mice, modems, etc, Keyboards, monitors and other devices (such a  SCSI port for external scanners or disk drives) also exist – and by and large they’re all different. The back of my old PC is reminiscent of a plate of spaghetti…

Wouldn’t it be nice, then, if someone were to come up with one simple connector that could handle all manner of peripherals?

Enter the Universal Serial Bus

In theory at least, that’s what USB – Universal Serial Bus – was designed to do. The standard, drawn up by a group of leading computer and telecoms companies (Intel, Compaq, DEC, IBM, Microsoft, NEC and Northern telecom), can mean that up to 127 devices can all be connected to the PC via this single kind of connector – with no need for internal adaptor cards.

What’s more, USB devices can be connected to the PC while it’s up and running – unlike internal card-type peripherals.

Data travels along thin cables between the PC and the device at 12 MEGAbits per second – and this is pretty quick. We’ve even heard of digital audio processing for heavy-duty professional use in concerts, broadcast and recording being controlled by a single (albeit long) USB cable and associated devices.

Most PCs these days are supplied with USB capability, and as you will see from our reviews sections, more and more hardware is coming on to the market specifically for USB PCs. Already there are printers, digital cameras, modems, joysticks and mice, scanners, audio devices, storage devices and even telephones that can use this means of working with your PC.

OK, what does it really mean for us?

The downside is that although the theory is that USB devices can even draw their power from the USB connection, eliminating the need for "wall-wart" mains adaptors, the practise seems to be otherwise. There’s also the point that USB devices make an impact on the processor – often badly so, so a slowish PC could have problems coping with a demanding USB device.

However, the upside is that the need for different kinds of connecting cables is largely eliminated – you just need USB cables with the appropriate version of the plug (yes, there’s more than one – this is computing after all!).

If we were to only buy USB equipment, the need to open the cases of our PCs to add cards will also disappear – certainly a good thing for those of us who are nervous about messing about near all those wires and chips. Monitors and keyboards already provide extra sockets for USB devices, and although the future may not be wireless, the wires we will have to put up with will be the same (ish) for all kinds of devices – and much smaller than the parallel and SCSI cables we may have reluctantly grown accustomed to!

But my machine doesn’t have USB – how can I join in?

The next PC or motherboard you buy will almost certainly support USB, but if you don’t want to wait until then, there are add-ons which can connect to your PC by more conventional means, and offer you a degree of USB compatibility. But, be aware that for your Windows operating system to be capable of using USB, you will need to be running Windows 98 or later.