Setting up Your Computer –
Sockets
The back panel
The following images show two versions of the "back panel" – the section of the main internal electronic board – the motherboard – which is accessible at the back of your computer. This is where most of the cables for your various devices are plugged in.
The white numbers on these images match those in the left column of the following table. The colours in that column indicate the standard colours of each type of connection.
Manufacturers of the ports (or sockets) and their matching plugs usually follow this standard – but not invariably.
It's best that your PC is switched off before connecting or removing
any plugs. USB connections are the exception to this rule, although even
they require special precautions if the associated USB device is an external
disk or a flash drive.
This is the back panel of a computer designed for a separate graphics
card.
It has two network connections but no display connection.
This has two display connections — one analogue and one digital — and
a FireWire connection.
It has no parallel port and no serial port, neither of which are likely
to be needed unless
you have an old printer or a very old external modem or mouse.
| Standard Colour | Connection Functions | Connection Type |
|---|---|---|
| 1 | PS/2 mouse connection. | 6 pin mini-DIN |
| 2 | PS/2 keyboard connection. | 6 pin mini-DIN |
| 3 | USB ports. These are
used for printers and scanners, USB keyboard and mouse, digital
camera, external hard drives and flash drives, wireless transmitters
and many other devices. Older PCs will have USB 1.0 ports, which look the same as USB 2.0. USB 2.0 is 40 times faster. This is of little consequence for the keyboard, mouse and home printer, but makes a huge difference when transferring data such as photo, video and sound files. |
USB Type A |
| 4 | FireWire or IEEE 1394. Used mainly for external drives and camcorders. Some FireWire devices can be "daisy-chained" in series so that more than one may be used with one socket. The second device plugs into the first and so on. | IEEE 1394 |
| 5 | Parallel port for older printers. | 25 pin D |
| 6 | Serial port. Rarely used in modern PCs. | 9 pin D |
| 7 | Analogue VGA. For connecting your standard monitor (screen). | 15 pin VGA |
| 8 | DVI - digital video input. Use this for monitors with a digital connection. | DVI |
| 9 | S-Video for connecting to a TV. | 4 pin mini-DIN |
| 10 | Composite video. | RCA jack |
| 11 | Audio input. Not good quality audio. | 3.5 mm jack |
| 12 | Audio stereo output for main speakers or headphones. | 3.5 mm jack |
| 13 | Microphone audio input. | 3.5 mm jack |
| 14 | Audio output for rear speakers. | 3.5 mm jack |
| 15 | Audio output for right-to-left speaker. | 3.5 mm jack |
| 16 | S/PDIF digital audio output. | 3.5 mm jack |
| 17 | Game port / MIDI for a joystick. | 15 pin D |
| 18 | Ethernet connection. Connects to your network router and/or high speed modem. | RJ-45 |
| 19 | Centre / sub-woofer | 3.5 mm jack |
The front panel
Most newer computers have extra sockets on the front of the case, often hidden behind a hinged or sliding cover. These are useful for plugging in headphones, cameras, video cameras, external discs and other devices which are to be used temporarily.
This one of mine has a microphone jack, a headphone jack, 2 USB 2.0 ports and a FireWire port.
The power supply
These vary in appearance, but the image below is typical.
At the back of your computer, beside a fan intake, you'll see something
similar to this:
Power plug, isolating switch and voltage selector
Power connection
The female connector of your main power cable fits into the 3 pin socket shown above at top right. The other end of the cable plugs into your wall socket, surge protector or uninterruptible power supply.
On/Off switch
The isolating switch (a "rocker" switch) shown at top left is in the "ON" position, with the "1" pressed down. Keep it OFF ("0" pressed down) until all your other cables are plugged in and the PC is ready to go.
Voltage selector
The voltage selector (bottom right above) should be already set to your local power supply voltage. North America and mainland Europe are usually 115V. The U.K., Australia and New Zealand usually 230V.
The switch is usually red like this one, but not always – black and grey are common colours.
This setting is very important! If it's incorrectly set, the switch can be slid to the correct position using your fingernail or a screwdriver tip.
On some computer power supplies the voltage is detected automatically. In that event, you won't have one of these slider switches.