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Computer ports explained | How many ports are there ?

by Mrinal Saha
How many ports are there

Many of computer users have heard terms like USB, HDMI port, firewire, RJ 45 but only a few know about them,  in this post we will see how to identify the different ports and understand which devices use which plugs and ports.

Computers come full of holes (ports) where every port has its use. These ports change from time to time, and we need to upgrade them accordingly. To keep track with the latest technology, it is important to know the basics about these ports.

How many ports are there

  1) USB  

Universal Serial Bus port is a small rectangular port that comes with every computer. A single USB port can be used to connect up to 127 devices such as mouse, modem, keyboard or external hard disk.  These USB ports come with three standard versions- USB 1.1 (obsolete), 2.0, and 3.0.

Computer ports explained-usb 

The major difference is speed. USB 1.1 could transfer data up to 12 Mbps. USB 2.0 (High-Speed USB)  transmits a max of 480 Mbps. But it’s only USB 3.0 which transfers data at an unbelievable rate of 4.8 (10x than USB 2.0) Gbps.


  2) HDMI: 

High-Definition Multimedia Interface  carries both video and sound, making one less cable for video 

Computer ports explained-hdmi

Or audio. This gives high definition video output and has the ability to send audio to the different format.



If you have old PC, you may have seen that, but nowadays they are not that common. Serial port has nine pins, and the parallel port has 25 pins. Today these have been replaced by USB interface. The basic difference between serial and parallel ports is that of the speed. The parallel port is needed for high-speed connection like printers.



serial port

parallel port





These look similar to our telephone line connection. The only difference between the two is that RJ45 is bigger in size and has eight pins in them whereas RJ11, that we use for our telephone lines, has only six pins. So you can tell the difference by simply looking at them. The usually support 10-1000 Mbps connection. Used mainly for data transfer.

Computer ports explained-rj-45



These are the small round shaped ones consisting of 6 pins. Both ports .ie. The ones for mouse and keyboard look the same. The only difference comes in their color. The purple one is for keyboard and green is for the mouse. But nowadays it has become a lot easier as we have USB ports for mouse and keyboard.


  6) FIREWIRE : 

Like serial and parallel ports, firewire is outdated now. You would not find it in new computers. The FireWire port has been in common use since 1995 when Apple, Inc. began to include the port on some digital camcorders

-Computer ports explained

  7) E-SATA: 

They are found on the latest computers. These let you plug in the newest breed of portable hard drives with extra speed and larger capacity. One reason why people prefer e-Sata over USB is that the transfer rate is fast, really fast. Currently, there is a 1.5 Gbps and a 3 Gbps Standard, way much more quickly than USB 2.0  and firewire.

e-sata | -Computer ports explained

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