Have you ever really took a look at the backside of your PC?

It's fairly obvious what most of those connectors are and what they do, such as Monitor, Mouse, Keyboard, printer, speakers. But what about those little square looking connectors. They are USB which stands for Universal Serial Bus. The are other sockets known as serial ports which can connect a mouse, printers, scanners ect. However the USB connector is something you really need to get to know. They are becoming increasely more prevelant and faster.

If your PC /Laptop was built after 1998 and it uses Windows 98, Windows 98SER, ME, 2000 or XP and now VISTA, then it probably has at least one USB socket and could have up to six. Windows 95 did not support USB very well and also Windows NT so don't try using it, as you will get frustrated trying to get it to work.

USB is by far the simplest, and the commonest, way of connecting peripherals to a PC. The plugs and sockets are easy to spot.

There are two basic styles: the flat lozenge-shaped Type A plug and socket, or upstream port, which you will find on your PC; and the smaller square-shaped Type B connector or downstream port, which is fitted to most peripherals. There's also a Mini USB downstream port connector for pocket-size gadgets.

If you look closely at a USB connector you will see four pins, two of them (pins two and three) carry data between the PC and peripheral, the other two are connected to ground (pin four) and a five volt DC supply (pin one), which is used to power small devices with a current drain of no more than 100 milliamps.

 

 

USB cables can be up to five metres (16.40 feet)in length. Cable runs can be extended in multiples of five metres, using gizmos called hubs.

 

 

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One of the main advantages of USB is that it is hot swappable - in other words, you can connect and disconnect a peripheral without shutting the PC down. Windows (and the Mac and Linux) operating systems automatically recognise USB devices and load the appropriate driver software, assuming it is installed on the computer, as soon as the connection is made.

If Windows can't identify the peripheral, or find a suitable driver, the New Hardware Wizard starts and you will be prompted to load the appropriate installation disk.

Up to 127 USB devices can be daisy-chained together and connect to a single PC - Hope you have room for all those gadgets...

With so many new gadgets coming on to the market, the one or two sockets fitted to most PCs and laptops are woefully inadequate.That is why newer motherboards will have up to 5-8 on the back and a couple internal ones. You can add USB either with a HUB or with a Card fitted inside of the computer.But it's easy to add more using a hub.

There are several types of hub. The simplest and cheapest work like multi-way mains extension sockets and provide several outlets (usually four) from a single USB connection. These are really only suitable for small low-power devices, and peripherals that have their own power supplies, such as printers.

More elaborate powered hubs come with a plug-in mains adaptor so they can be used with several USB devices that require an external supply, such as modems, memory card readers and web cams.

You can also get multi-way hubs that live inside the PC, on a card that fits into a PCI adaptor slot on the motherboard. These are fully powered and work like the PC's standard USB sockets.

 

 

 

 

 

The USB 1 system, which is the one fitted to most older systems carries data at between 1.5 and 12 megabits per second. That is more than enough for printers, scanners and keyboards. However, it is a tad slow for shifting really large volumes of data around, for storage devices and digital video, for example.

To overcome the speed limitation a new standard was established in 1999, called USB 2 or USB Hi-Speed. USB 2 is up to 40 times faster than USB 1 and on a good day, with the wind in the right direction, data transfer rates of up to 480Mb/sec are possible.

New port adaptors are required for USB 2 (now fitted to some recent motherboards as standard) but it uses the same connectors and is backwards compatible, so USB 1 devices can be used on a USB 2 PC.

However the data rate of the bus drops to a maximum of 12Mb a second to accommodate the slower device. Support for USB 2 is available for Windows ME, 2000 and XP.Microsoft has decided not to support earlier versions of Windows (98 and SE), but third party drivers are available from port adaptor manufacturers.

USB is generally very reliable and when things go wrong it's usually the fault of the driver software, but a surprising number of problems can be solved by just swapping the plugs around.