Patrick, a computer technician, is a dedicated writer who wishes to make the world better by informing individuals who seek more knowledge.
This article describes the nature of each of the main external computer ports, their connector types, and common modes of use.
Computer Ports and Connectors
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 as a CD player.
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.
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.
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.
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:
- It supports plug-and-play: Once connected, the device is configured automatically without any user input.
- 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.
- It supports 127 peripheral devices (you can make use of a USB hub for more additional ports).
- It provides power to connected devices.
Data Transfer Rates of Typical USB Ports
|USB VERSION||YEAR||DATA TRANSFER RATE IN Mbps|
1.5 & 12
1.5 & 12
USB 2.0 (high speed)
USB 3.0 (super speed)
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
Question: What is the use of a VGA port?
Answer: This is the port where you connect the VGA cable (the cable that takes data to your monitor). The Video Graphics Array (VGA) port is a three-row 15-pin DE-15 connector. Remember there are different video cable types such as a VGA, DVI, or HDMI.
© 2011 Patrick Kamau
Priscilla Asantewaa Brenyah on March 19, 2020:
what if the functions of parallel ports
Patrick Kamau (author) from Nairobi, Kenya on November 10, 2019:
Thanks Destiny ejikem. I am glad you enjoyed and learned something here.
Destiny ejikem on November 06, 2019:
This is a wonderful blog
ameobi on January 29, 2019:
this website is useless
Mk daniels on January 27, 2019:
Thanks , i just learned something new todau
DIANNEEEEEE on October 18, 2018:
Thanks! A lot!!!!
gdfgdfgdf on August 05, 2018:
thanks for the info.
Fiddelford on August 01, 2018:
Where is the SATA?I only saw eSATA But on the other hand thanks BRO for this hub.
steward chizu simpungwe on March 13, 2018:
thank you very much, but there are still some two ports which i can not find this are, the telephone line out port and the cable tv port
Patrick Kamau (author) from Nairobi, Kenya on October 09, 2017:
Hello, Charmaine, There are a number of devices you can connect - eSATA external devices are basically external storage devices, such as Optical Disc Drives (ODD, DVD), Hard Disk Drives (HDD), HDD Arrays and HDD Docks. Additionally Network Attached Storage devices can also have eSATA ports for expansion using additional storage devices.(NAS)
Charmaine on October 05, 2017:
What is the use of the esata port? Not the cable
mweemba rodger ( zambia ) on December 18, 2016:
I have liked you contributions . keep it up brother
Patrick Kamau (author) from Nairobi, Kenya on March 19, 2015:
You are much welcome edwin tush and thanks for the visit.
edwin tush on March 17, 2015:
i have learnt a lot thank you too much
Patrick Kamau (author) from Nairobi, Kenya on February 03, 2015:
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 on January 27, 2015:
What is a coaxial S/PDIF Out Port? I would guess that it is an audio output, but I am not certain.
Patrick Kamau (author) from Nairobi, Kenya on October 03, 2014:
You are welcome @crystal white
crystal white on September 24, 2014:
nice hub. thank you
Patrick Kamau (author) from Nairobi, Kenya on August 27, 2014:
You are welcome @meerub
meerub on August 17, 2014:
Patrick Kamau (author) from Nairobi, Kenya on August 15, 2014:
Thanks @bhanu for the nice words.
bhanu on August 14, 2014:
nice job hub all the things are elaborated in a simple language which can be understand by any one
Patrick Kamau (author) from Nairobi, Kenya on July 21, 2014:
Thanks lovely idos glad that you liked it.
lovely idos on June 10, 2014:
Patrick Kamau (author) from Nairobi, Kenya on March 14, 2014:
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.
Chris Gore Tamania on March 14, 2014:
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.
Patrick Kamau (author) from Nairobi, Kenya on December 15, 2013:
You are welcome gerald delgado
gerald delgado on December 10, 2013:
im glad! to see tthis because me and my friends will do same this
Patrick Kamau (author) from Nairobi, Kenya on July 10, 2013:
Thanks a lot receivetipstricks, for your visit and comment. I am glad you liked it.
Mrinal Saha from Jaipur,India on July 10, 2013:
This is well explained thanks,,
Patrick Kamau (author) from Nairobi, Kenya on April 10, 2013:
anni, port function is just a matter of which device is connected to that specific port.
anni on April 09, 2013:
i want to know port and connector function
Patrick Kamau (author) from Nairobi, Kenya on February 12, 2013:
Thanks gal, for approving this work. Hope you will check other articles.
gal on February 12, 2013:
its very useful ..........
Patrick Kamau (author) from Nairobi, Kenya on July 01, 2012:
Elizabeth, what can I say? I am humbled. Thanks for reading and commenting.
Patrick Kamau (author) from Nairobi, Kenya on July 01, 2012:
I agree with you doraemon, and you are also nice because you have read and commented. Thanks.
Patrick Kamau (author) from Nairobi, Kenya on July 01, 2012:
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.
elizabeth on June 30, 2012:
doraemon on June 30, 2012:
harish on June 30, 2012:
Buddy where can i get list of connectors and no: of pins?
Patrick Kamau (author) from Nairobi, Kenya on May 30, 2012:
Jues, you are welcomed to read more of my computer tutorials. I am glad you found it useful. Thanks for reading and commenting.
Jues on May 30, 2012:
i so much thank you for your contribution toward the parts and component of computer.
Patrick Kamau (author) from Nairobi, Kenya on May 27, 2012:
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.
HM on May 26, 2012:
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???
Patrick Kamau (author) from Nairobi, Kenya on April 30, 2012:
Thanks M Salah, for reading and commenting, your support counts.
M Salah on April 30, 2012:
Thanks for your iforts about helping us to such valueble topic.
thanks a lot
Patrick Kamau (author) from Nairobi, Kenya on April 27, 2012:
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.
emmanuel on April 27, 2012:
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:email@example.com?i will really appreciate it.thank you...
Patrick Kamau (author) from Nairobi, Kenya on March 03, 2012:
Thanks too for visiting and commenting.
unknown on March 02, 2012:
thanks a lot.. i have got what i was searching for.. thanks again!!
Patrick Kamau (author) from Nairobi, Kenya on November 19, 2011:
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.
Ker Simon on November 18, 2011:
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; "firstname.lastname@example.org" THANKS!