Ports and Connections

Make sure you can tell which connection does what

Working out how to hook up your peripherals and their cables can seem daunting. The back of a modern computer has more connections than Max Clifford - and these 'ports' can be used for anything from a keyboard to a digital camcorder.

Learning which ones do what isn't just about pushing the cable into a socket until something gives, as different ports transfer data at different speeds. If, after reading this, you realise you're stuck with a slow, older connection, you can upgrade to faster ones by installing the appropriate PCI card inside your computer.

In other words

Dedicated A port with one specific function.
Hot swappable You can attach and detach peripherals while the computer is on.
Hubs A way to add extra connections - you could, for instance, plug a four-port USB hub into an existing USB port.
Mbps Data transfer speeds are measured in megabits per second.
Plug and Play (PnP) Devices that announce themselves to the computer so it can detect them automatically.
Powered Non-powered hubs draw power from the computer; powered ones need their own power supply (but are advisable if you're connecting several devices).
Snappable You just push these connections in the port - there's no chance of losing your patience or the tiny screws that non-snappable ones use.
Universal Works with several applications.

What's the Connection?

USB 1.1 Universal Serial Bus (USB) 1.1 is the port of choice for most manufacturers. Its 12Mbps speed is suited to anything that transfers low to medium amounts of data, such as scanners, printers and keyboards. Snappable and hot-swappable, USB is so common that people with lots of devices run out of ports. Fortunately, you can plug a USB hub, with extra ports, in to an existing connection. Up to 127 devices can, in theory, be connected to one USB port this way - but this isn't advisable as they would share its transfer speed.

PS/2 A typical modern computer has two snappable PS/2 ports, which are colour coded for your keyboard and mouse. If you have a USB mouse or keyboard, a USB to PS/2 adaptor will free up a USB port. The PS/2 connection is slower but this shouldn't matter as a keyboard can transfer data only as fast as you can hit the keys. Older computers use larger DIN ports to connect the keyboard, and older mice hook up to a COM port.

Parallel This port was traditionally used to connect a printer, although the improved speed (24Mbps) of modern parallel ports means they can be hooked up to web cams and scanners. They need heavy-duty cables and have fallen out of favour due to the advantages of USB.

COM Most computers have two COM (also known as Serial or RS232) ports, which are slow (0.115Mbps) and unintelligent, but cheap and easy-to-use. They were the standard port for dial-up modems and older mice, but have mostly been superseded by USB.

Soundcard connections These typically include a 'line-out' for speakers, a 'line-in' (to hook up a hi-fi, say) and a microphone socket. Most soundcards have a joystick port which, with the right cable, can also be used to connect MIDI devices, such as a keyboard. Advanced cards may have digital audio connectors.

VGA and DVI The VGA and the newer, and rarer, snappable DVI port are on your graphics card. They are dedicated for use with visual devices, such as a monitor or projector (DVI gives a better picture with flat-panel screens). Graphics cards can also have a video input to hook up a camcorder and a TV-out port (to watch DVDs, say, on your TV).

SCSI Pronounced 'scuzzy', a Small Computer System Interface (SCSI) tends to be found on Macs (apart from the iMac) and more advanced Windows computers. Its speed is typically between 80 and 1,280Mbps - there are several standards that vary in performance and price.

USB 2.0 These are extra USB 2.0 ports that we fitted. They run at 480Mbps (40 times the speed of 1.1) and are backwards compatible (you can plug 2.0 devices into 1.1 ports and vice versa - but data transfer is at the 1.1 rate).

FireWire IEEE 1394a (known as 'FireWire' by its inventors at Apple) has an impressive speed of 400Mbps. This snappable, hot-swappable port is most commonly found on digital camcorders and is also used with other high-end devices, such as disk drives. An upgrade is already in the pipeline - IEEE1394b promises a speed of 800Mbps.

Ethernet Also called network interface connectors, there are three types used to create a home computer network or connect a broadband modem, typically at 10 or 100Mbps.

Modem This is where you plug in your phone line to access the internet.