A port is simply a gateway allowing your computer and something else to exchange data. When you plug something into a port on your computer, you are allowing it to exchange information with the computer.
The primary reason ports exist is because they allow for relatively easy upgrade and removal of computer peripherals. Imagine if your printer were attached to your computer, and you had to solder a new printer onto the old connection and you will appreciate ports. Having ports also allows you to use a single peripheral with multiple computers. This is especially important with USB flash drives, which allow for easy data transfer. Because of ports, you can choose to have headphones, an external hard drive, a TV tuner card and a printer connected to your laptop at home or…
Modern computers come equipped with a few different types of ports, each with a different shape and each with a different raison d’etre. Below you can find an explanation of each type of port you are likely to find on a modern computer.
• USB port – this is one of the most important ports on a modern computer. It looks like a skinny rectangle with a “tongue” that takes up half of the rectangle longways. USB ports are used for almost everything – you can connect external hard drives, headsets, speakers, TV tuners, video cards, sound cards, flash drives, CD or DVD drives, and almost anything else you can think of. You can even connect USB hubs to USB ports and make one port into five! If you have bought a computer in the past seven years, it almost certainly has a USB port. You may hear about different numbered “versions” of USB – eg, USB 2.0, USB 1.1, USB 1.0. Unless you have something that needs the higher data transfer rate of USB 2.0 (a device that is transferring raw video perhaps) most USB devices will work in any version of USB port. A USB 1.1 port is slower, and it will take more time to transfer your files, but it will work.
• Firewire – these look like skinny rectangles with the corners cut off on . You may see one or perhaps two of these in a computer. They tend to be used for audio and video devices, such as VHS to DVD converter kits and external audio recorders. They also can be used to connect many digital camcorders to the computer. There are two versions – Firewire 400 and Firewire 800 – but both use the same port, and you will likely not need to be concerned about this at all unless you have a very special hardware configuration that requires the newer version.
• VGA port – the monitor port. This is usually blue on modern computers and looks like a three rows of holes for the pins on the connector. Modern computers are likely to have one of these and a DVI port, or just a DVI port. If your monitor and your computer support DVI, use it – it is digital (vs. analog for VGA) and provides a higher quality signal, meaning a better-looking display.
• DVI port – the new monitor port. Looks like a weird configuration of square holes and holes for pins a bit more than an inch long. If you can use this port with your monitor, do so.
S-Video port / Composite video port these are both used to hook your computer up to a television, projector, or some other video device. An S-Video port looks like a PS/2 port, but with a different pin configuration. A composite video port is just an RCA connector like the yellow connectors on a television or projector. When using these, a special keypress or setting may be required to make the computer output to the television. You may have to change other video settings as well check your manual and your software to see what you have to do to make the output display on a television.
HDMI port still uncommon, but may become more common as time proceeds. These ports are used for high-definition video and audio. In a computer they may be used to connect to an HDTV or to a monitor that supports HDMI. They are very narrow, and have no pins like DVI or VGA.
• TV tuner port – used to connect a coaxial cable, usually from your Cable or Antenna. These are just normal coaxial connections; they are circular with threads on the side for a coaxial cable end. If you have more than one, make sure you check the manual and see which one you need to use – some cards have radio and TV tuners that both connect with coaxial cable.
• Audio ports – these look like typical headphone jacks, ie round holes. They can be used for speakers, microphones, and other audio devices. The ones typically found on a simple sound card are the speaker port, the microphone port, and the line-out port. If they are color coded, green is the speaker port, red is the microphone port, and blue is the line-out port, used for hooking your sound card to other audio equipment, like a receiver. If not, look for pictures or abbreviations that signify which port is which eg, a microphone for the microphone port, or an arrow pointing away from a musical note for a line-out port. The speaker port is used to connect speakers or headphones for sound output. The microphone port is used to connect a microphone to record into the computer. This is also typically used for the speaking end of headsets. Line-out ports are for other audio equipment, such as a power amplifier or integrated receiver. You can hook your computer up to your stereo system using line-out ports.
There are other types of audio ports. The line-in port is used to record from external devices. Hook an audio device up to your computer and make sure to choose “Line In” in your recording program. Computers also can have more than one speaker port. Many modern computers have three or four, for rear and side speakers. Consult your sound card’s manual for instructions on how to set up a surround sound speaker system.
• SPDIF (Optical and Coaxial) port: These are like line out and line-in ports, but they transfer the signal digitally instead of analog. An optical port looks like a little box with a door or a plug that can be pulled out it is used with optical cable. A coaxial port looks like a normal RCA jack, like you would see on the back of slightly older TVs. It is NOT the same type of port it looks the same, but it transfers different data. These ports are mainly used to connect your computer to an external receiver or an external device to your computer. Make sure you tell your recording program to record from the Digital Line-In if you are recording over an Optical or Coaxial line-in.
• Joystick port/MIDI port: Used for a joystick or, with the proper cable, to hook MIDI devices (such as a keyboard) to your computer. These are becoming less and less common USB now handles both joysticks and MIDI devices. However, if you have one of these, it looks like a Parallel port but smaller. It is wider than a VGA port but smaller than a parallel port.
• Parallel port – Not as common on modern computers, this port looks like two rows of pinholes for connector pins and is about two inches wide. This is mainly used for older printers. It can be used in certain circumstances to transfer files or to hook up other random components, but it is rarely used for anything but printers anymore.
• Serial port – Very uncommon on modern computers, this port usually looks like two rows of pins and is about an inch wide. These have been replaced in most instances by other ports, especially USB ports, but are still useful if you have an old PDA or something that has a serial connection. Much less common is a DB-25 serial port that looks a lot like a parallel port – you will probably never see this, but just in case, parallel ports typically have pictures of printers next to them.
• PS/2 port the mouse and keyboard port. These are round, about a centimeter in diameter, with holes where pins on the cable would fit. These are becoming less and less common as USB develops. They are only used for mice and keyboards. Plug the keyboard into the port with the picture of the keyboard and the mouse into the port with the picture of a mouse. If you have a USB keyboard and a PS/2 keyboard port, and your keyboard won’t work on boot, try plugging in a PS/2 keyboard some computers don’t register USB keyboards until the OS starts.
• Ethernet port – Looks like a phone jack, but wider and overall larger. This is a network port – it allows you to connect to a hardwire network. You connect an ether net cable to a router or hub or other network device and you now have access to a network. Do not confuse this with the modem port – it looks similar, but is larger and usually has little lights nearby.
• Modem port – Looks like a phone jack; in fact it is exactly like a phone jack. If you have dial-up Internet, you connect your Internet phone cord to this port. If you have more than one, check for a picture of a phone with an arrow pointing to it or something similar – this is to hook up a phone so that you don’t have to buy a splitter or run a new cable. Plug the phone into this port and the cable from the wall into the other.
• Power port – Looks somewhat triangular with three pins for desktops; typically a round hole, perhaps with a pin in the center for laptops. This is used to hook the power adapter or cable to your computer to give it power and charge a laptop’s main battery.
Laptops often have a special type of port that allows them to connect to a docking station. These vary in appearance, and are typically on the bottom or back of the laptop. The only thing that will fit in one of these docking ports is a docking station or port replicator for your laptop. Docking stations allow you to have a “base” at home or work where your laptop is connected to various components that are useful at home but are not necessary on the road. You can use your speakers and printer at home, and when it is time to go, simply eject the laptop from the station and be on your way. Port replicators simply add ports that are missing on your laptop due to size concerns. These tend to be more portable, and are useful if you need certain ports on the road that your laptop does not have built-in.
These are the most common ports you will find on a modern computer. If you are able, look at the back of your computer and try to identify these ports for yourself. If you are having trouble, ask a friend who knows computers well. With even a brief knowledge of what each one looks like and is used for, you will be well-prepared to hook peripherals to your own computer.