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Computer Ports and Their Functions

Updated on October 26, 2016
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Patrick is a dedicated technology writer wishing to make the world better by informing those people seeking for more knowledge.

Computer Ports and Connectors

This article describes the nature of each of the main external computer ports, their connector types, and common modes of use.

A port is a connector at the back or side of a computer where you plug in an external device such as a printer, keyboard, scanner, mouse, or modem. This connection allows instructions and data to flow between the computer and the device. These computer ports are also commonly referred to as the Input/Output ports (I/O ports).

Most Connectors are Polarized

Most connectors are polarized, permitting the cable to be plugged in only in one correct direction. The keyboard and mouse use "PS2" connectors which are color-coded: The purple connector is for the keyboard while the green connector is for the mouse.

Connecting a Keyboard/Mouse to Your Computer

To plug in a keyboard or mouse cable, first match the cable to the connector. Rotate the cable until the connector keys match up with the receptors, then push the cable in. Be sure not to force the connector because you will end up bending the pins.

The parallel port, serial port, and video port all use D type connectors (DB-25M, DB-9M, and DB-15F, respectively). These are called "D connectors" because of their shape, which permits the cables to be plugged in only one way.

The audio jacks are the most confusing connectors on the back panel. Although the jacks are sometimes color-coded, the devices that plug into them rarely are. You can try using the identifying symbols stamped into the metal next to them.

The green jack (audio out) is where you plug in your left speaker. Only one speaker plugs into the computer: The right speaker plugs into a jack on the left speaker.

The red jack is where you plug in your microphone. The center jack (audio in) is where you plug in audio from another device, such a CD player.

Connector Types

A computer cable connector is the part of a cable that plugs into a port or interface to connect a device to the motherboard or another device. Most connectors are either male (containing one or more exposed pins) or female (containing holes in which the male connector can be inserted). A number of different connector types are used to connect various external devices to the computer.

DB Connectors

This connector type is most often associated with the serial, parallel, and display monitor ports. DB stands for D bucket connector and the full connector designation (e.g. DB25 male) refers to the number of pins in the connector and whether the connector is a male (plug) or female (socket) type.

Note: If a DB-type port uses a female connector, the cable associated with the port will require a male connector to ‘mate’ correctly and vice versa.

The standard 15-pin VGA connector was derived from an older 9-pin design; consequently, the plugs have 15 pins in a connector shell originally designed for 9. The only way to make more pins fit was to make them thinner, but this also makes them more prone to bending, so always take care when plugging in video leads because bent pins are hard to straighten without breaking them off. The monitor might work with a bent pin, but you will not get the correct colour output.

The DIN Connectors

Another type of connector is the DIN connector. DIN is an abbreviation for Deutsches Institut für Normung, or German Institute for Standardization, which is a German manufacturing industry standards group. DIN connectors are round with pins arranged in a circular pattern. This type of connector was used widely for PC keyboards, MIDI instruments, and other specialized equipment.

We have two types of DIN: Full DIN and Mini DIN.

Full DIN (or five pin DIN):

This connector has five pins that are arranged in a circular pattern. This type of connector was commonly used for older AT-style computer keyboards that are obsolete nowadays.

Mini DIN:

This connector has six pins as well as a keying block. This interface was first used on the IBM PS/2 personal computer. For this reason, the connector is often called a PS/2 connector. This connector, which had become the industry standard for connecting keyboards and mice, has been superseded by the USB connector.

Audio Connectors
Audio Connectors

Audio Connectors

Most of the audio connectors on a PC are 3.5 mm mono and stereo jack plugs, as used on most portable domestic audio equipment. Using them, you connect computer speakers or headphones to get sound out of your computer.

The USB Port

USB stands for universal serial bus. This is an industry standard computer bus developed in the mid-1990s that replaced some ports we used, for instance, the PS/2 ports for mouse and keyboard.

The USB standard defines the cables, connectors, and communication protocols used in a bus for connecting devices, enabling communications and providing power between the PC and the device. After it was developed, the USB became the standard for connecting most computer peripheral devices such as modems, keyboards, mice, printers, scanners, digital cameras, disk drives, PDAs, smartphones, and a host of other devices.

Features of the USB Port:

  1. It supports plug-and-play: Once connected, the device is configured automatically without any user input.
  2. It supports hot swapping: Devices can be plugged and unplugged while the computer is powered on. Note that it is always recommended to eject manually using the "safely remove hardware" instruction before unplugging from the computer.
  3. It supports 127 peripheral devices (you can make use of a USB hub for more additional ports).
  4. It provides power to connected devices.

Data Transfer Rates of Typical USB Ports

USB VERSION
YEAR
DATA TRANSFER RATE IN Mbps
USB 1.0
1996
1.5 & 12
USB 1.1
1998
1.5 & 12
USB 2.0 (high speed)
2000
480
USB 3.0 (super speed)
2008
4800
USB data tranfer rate

Do you know most of the computer ports at the back of your computer?

See results

© 2011 Patrick Kamau

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      mweemba rodger ( zambia ) 4 months ago

      I have liked you contributions . keep it up brother

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      Patrick Kamau 2 years ago from Nairobi, Kenya

      You are much welcome edwin tush and thanks for the visit.

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      edwin tush 2 years ago

      i have learnt a lot thank you too much

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      Patrick Kamau 2 years ago from Nairobi, Kenya

      Your guess is 100% right TTGReviews. Sony/Philips Digital Interface Format is surely an audio output port. It is used with home theatres and other digital high fidelity systems.

    • TTGReviews profile image

      TTGReviews 2 years ago

      What is a coaxial S/PDIF Out Port? I would guess that it is an audio output, but I am not certain.

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      Patrick Kamau 2 years ago from Nairobi, Kenya

      You are welcome @crystal white

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      crystal white 2 years ago

      nice hub. thank you

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      Patrick Kamau 2 years ago from Nairobi, Kenya

      You are welcome @meerub

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      meerub 2 years ago

      thanks

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      Patrick Kamau 2 years ago from Nairobi, Kenya

      Thanks @bhanu for the nice words.

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      bhanu 2 years ago

      nice job hub all the things are elaborated in a simple language which can be understand by any one

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      Patrick Kamau 2 years ago from Nairobi, Kenya

      Thanks lovely idos glad that you liked it.

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      lovely idos 2 years ago

      very creative

    • Patkay profile image
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      Patrick Kamau 3 years ago from Nairobi, Kenya

      Thanks Chris Gore Tamania, I am glad you found what you wanted, all my important notes about computers you can find there here on other hubs.

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      Chris Gore Tamania 3 years ago

      Superb! At least I've got what I wanted on your web page. It would be even better if you could send me more of computing notes because Im a computer teacher at Popondetta Secondary School here in Papua New Guinea.

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      Patrick Kamau 3 years ago from Nairobi, Kenya

      You are welcome gerald delgado

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      gerald delgado 3 years ago

      im glad! to see tthis because me and my friends will do same this

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      Patrick Kamau 3 years ago from Nairobi, Kenya

      Thanks a lot receivetipstricks, for your visit and comment. I am glad you liked it.

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      Mrinal Saha 3 years ago from Jaipur,India

      This is well explained thanks,,

    • Patkay profile image
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      Patrick Kamau 4 years ago from Nairobi, Kenya

      anni, port function is just a matter of which device is connected to that specific port.

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      anni 4 years ago

      i want to know port and connector function

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      Patrick Kamau 4 years ago from Nairobi, Kenya

      Thanks gal, for approving this work. Hope you will check other articles.

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      gal 4 years ago

      its very useful ..........

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      Patrick Kamau 4 years ago from Nairobi, Kenya

      Elizabeth, what can I say? I am humbled. Thanks for reading and commenting.

    • Patkay profile image
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      Patrick Kamau 4 years ago from Nairobi, Kenya

      I agree with you doraemon, and you are also nice because you have read and commented. Thanks.

    • Patkay profile image
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      Patrick Kamau 4 years ago from Nairobi, Kenya

      harish, thanks for reading. For list of connecters and no of pins, you can try to Google. But since you have challenged me, I will be adding them into this hub soon. So keep checking.

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      elizabeth 4 years ago

      thanks ;)

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      doraemon 4 years ago

      nice

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      harish 4 years ago

      Buddy where can i get list of connectors and no: of pins?

    • Patkay profile image
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      Patrick Kamau 4 years ago from Nairobi, Kenya

      Jues, you are welcomed to read more of my computer tutorials. I am glad you found it useful. Thanks for reading and commenting.

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      Jues 4 years ago

      i so much thank you for your contribution toward the parts and component of computer.

    • Patkay profile image
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      Patrick Kamau 4 years ago from Nairobi, Kenya

      Thanks HM for your nice question. You will use the same splitter cable. And since you are getting the same info on both monitors, your connections are okay. So, the only thing you have to do is check your settings.

      You can try the following hoping you are using windows xp.

      On the Settings tab of the Display Properties dialog box, click Identify to display a large number on each of your monitors. This shows which monitor corresponds with each icon.

      Click the monitor icons and drag them to positions that represent how you want to move items from one monitor to another, and then click OK or Apply.

      Drag an item on your desktop across your screen until it appears on the alternate monitor. Or, you can resize a window to stretch it across more than one monitor.

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      HM 4 years ago

      how do i hook up 2 monitors to be able to drag screen from one to another when i only have 1 port to plug in to? i have a y splitter but when i hook up i only get same info on each screen and cannot drag? there is a green port on back of computer....is that for a 2nd monitor and what kind of cable does it require???

    • Patkay profile image
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      Patrick Kamau 4 years ago from Nairobi, Kenya

      Thanks M Salah, for reading and commenting, your support counts.

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      M Salah 4 years ago

      Thanks for your iforts about helping us to such valueble topic.

      thanks a lot

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      Patrick Kamau 5 years ago from Nairobi, Kenya

      Thanks emmanuel for reading and commenting. I want to keep on the good work I started. There is also an easy way you can be getting updates every time I post something, under my picture profile you can click on Subscribe to Patkay's RSS feed. Onec you subscribe you will be sure to get updates.

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      emmanuel 5 years ago

      i love the work u are doing.pls keep the good work up.pls can u continue to send me more of this to my email at:erufus23@yahoo.com?i will really appreciate it.thank you...

    • Patkay profile image
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      Patrick Kamau 5 years ago from Nairobi, Kenya

      Thanks too for visiting and commenting.

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      unknown 5 years ago

      thanks a lot.. i have got what i was searching for.. thanks again!!

    • Patkay profile image
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      Patrick Kamau 5 years ago from Nairobi, Kenya

      Thanks a lot Ker Simon, for going through my hub and commenting. I am also glad that you found what you wanted out of this page. I will be sending you more computer maintenance tips as you requested. Thanks again.

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      Ker Simon 5 years ago

      Bravo! I am glad to have gotten what I was looking for on you web page. I request if you can be sending me with computer system maintenance tips to develop my self. My E-mail; "kerterhide@gmail.com" THANKS!

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