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What is Computer Port?
A computer port refers to the interface between the peripheral devices and the system. Technically, a computer port is a software based linking point which is managed by the operating system of the computer.
In simple words, a computer port is a part of the device or a connection point and can be internal or external.
- The computer ports signify those slots or physical docking points located at the sides of a laptop computer and at the front or back of a desktop computer case.
- These ports are used to connect different peripheral devices directly to the motherboard of the computer by using specific types of cables for each.
- The key function of the ports is to transfer data by converting them from the raw form into meaningful information.
- These ports can be divided into two major groups such as serial ports and parallel ports that are further categorized on the basis of their physical form, protocol used for communication and other parameters.
Understanding Computer Ports
The ports of a computer are actually the slots on the motherboard where the cable is inserted to attach the peripheral devices.
In general, a computer port refers to the female end of a connector that is found on the motherboard.
However, it is perhaps enough to know for a newbie that a computer port is a point of connection or an interface between the computer and the external peripheral devices.
Some of the most common peripherals devices connected externally to the computer are:
- Monitor or display unit
- Flash drive and more.
The cable from these peripheral devices is plugged into the ports to connect to the motherboard and communicate or transmit data to it for processing.
It is for this reason a computer port is also referred to as a communication port.
Needless to say, each of these peripheral devices comes with different designs and points of connection.
Therefore, the ports also come in different shapes, technology and design.
Some of the most common types of ports that are found on a computer these days are:
- Serial port
- Parallel port
- PS/2 port
- USB port
- VGA port
- FireWire port
- Modem port
- Digital Video Interface or DVI port
- Ethernet port
- Infrared port and
- Game port.
These ports typically can be divided in two broad categories according to their respective types of the protocol used by them in order to establish a communication. These are:
- Serial ports – A serial port refers to an interface which allows connecting external peripheral devices using a serial protocol. According to this protocol one bit of data is transmitted at a time for every single communication line. The D-Subminiature or D-Sub connector is the most commonly used type of serial port. It typically carries RS 232 signals.
- Parallel ports – A parallel port, on the other hand, indicates the interface that allows the computer to establish a communication with the external peripheral devices in a parallel manner. This means that the data in this case is sent in or out in parallel. This process uses more than one wire or line to establish the communication. One of the most common examples of a parallel port is the printer port.
All these ports have different functions, varieties and designs and here are the characteristics of each of these ports with a brief introduction along with their applications.
Generally, the computer ports are found at the rear side of the computer but depending on the type and its use, a few can also be located at the front end of the panel or chassis. It also depends on the design of the computer itself.
As said earlier, there are two major types of ports and the characteristics of these ports are as follows:
The serial ports are used to connect older computer mouse or an external modem.
The two versions of the serial ports are 9 pin and the 25 pin model through which data travels at a speed of 115 kbps or kilobits per second.
The serial ports are also called the COM ports or communication ports and are quite cheaper in comparison to the parallel ports. It is easy to shield the serial ports from interference.
These ports usually have 25 pins. The parallel ports are also called the printer ports and LPT or Line Printer Ports.
These ports can transfer several bits of data at the same time because it uses parallel communication.
As for the other ports, the characteristic features vary and are as follows.
Types and Functions
Now, take a look at all the different types of computer ports one by one.
The PS/2 ports that are also referred to as mouse ports are typically used to connect an old mouse or a keyboard to the old computer.
Usually, most of these old computers come with two PS/2 ports, one for connecting the mouse, and the other to connect the keyboard.
The PS/2 ports were developed by IBM or the International Business Machines Corporation and introduced in their Personal Systems/2 series of computers which give these ports their name.
The PS/2 connectors usually come with two colors, green to connect the mouse and purple for connecting the keyboard.
These ports come with 6 pins and the pinout of PS/2 female connectors are the same for both the mouse and the keyboard.
This means that the computer will not recognize the device when it is connected to a wrong port.
Typically, these ports are considered as legacy ports now because the USB ports have outdated them.
There are a very few motherboards that come with this legacy port.
The power connector in a computer connects the power cord to the mains supply and has three prolonged pins.
These pins are placed at three vertices to make it look like a triangle.
There are different types of power connectors such as C5/C6 that are also called the ‘Mickey Mouse’ or ‘Cloverleaf’ power connectors with a capacity of 2.5 amps.
You will find these connectors in the portable projectors and most of the laptops.
There are also C7/C8 power connectors where the C7 variants are also called the ‘Shotgun’ sometimes and also have a power supply capacity of 2.5 amps.
These power connectors are used in cassette recorders, a few full-size AV devices, battery or mains operated radios, laptop computers, and video game consoles.
Then there are the C13/C14 power connectors with a power capacity of 10 amps where the C14 connectors are used to connect printers, monitors and other external peripherals to the power supply.
Older computers typically come with C13 power connectors on the panel to power up the monitor.
The FireWire ports can carry a huge amount of data at a great speed of about 400 mbps to 800 mbps.
These ports are typically used to connect video equipment such as camcorders to the computer.
This refers to the IEEE 1394 interface that follows the Institute of Electrical & Electronics Engineers high speed serial bus standard.
These ports were developed by Apple in the late 1980s and early 1990s. Typically, the FireWire ports are available in three particular variants such as 4 Pin FireWire 400 connector, 6 Pin FireWire 400 connector, and the 9 Pin FireWire 800 connector.
The modem ports connect the modem or modulator/demodulator of the computer to the telephone network to transfer signals.
The game ports typically connect a joystick to the computer but in the modern computers this port is replaced now by a USB port.
These IR or Infrared ports are used to send and receive infrared signals. These ports are typically kind of wireless-type ports but have a limited range of operation between 5 feet and 10 feet.
DB 25 ports:
DB 25 ports are one of the two variants of serial ports that are found in the computers.
These ports typically comply with the RS 232 standard which makes them different from the PS/2 ports and USB ports which are also serial, technically.
These DB 25 ports are a variant of the D-sub connectors and are considered to be the unique ports for RS 232 serial communication.
However, most of the applications did not require all the pins and hence it was used less as a serial port but more as a parallel printer port to replace the Centronics Parallel 36 pin connector.
DE 9 ports:
Lesser use of BD 25 resulted in the creation of DE 9 ports for serial communication following the RS 232 standards.
Also referred to as COM ports, these ports became the main port for establishing RS 232 serial communications.
These ports are also a variant of the D-sub connector but with an E shell. Still, these ports are often erroneously called DB 9 ports.
The DE 9 ports are also referred to as COM ports and they allow complete duplex serial communication between the peripheral devices and the computer system.
Some of the uses of the DE 9 port are to connect keyboard, mouse, modem, UPS or Uninterruptible Power Supplies and other external devices that are RS 232 compatible.
However, the use of both DB 25 and DE 9 ports for communication is not much today and these ports are now being replaced by USB and other types of ports.
Centronics 36 Pin ports:
These ports are parallel ports and are used to connect a computer with external peripheral devices such as printers and scanners.
The use of these ports was extensive before the USB ports came into the market. However, the Centronics port was replaced by DB 25 ports later on with a parallel interface.
The computer also comes with different sockets that are typically used to connect speakers and microphones to the sound card of the computer.
These audio ports carry audio signals. These ports may be either analogue or digital depending on the type of signals they carry.
One of the most commonly used audio ports is the 3.5 mm Tip, Ring, Sleeve or TRS connector which are also known as the surround sound connectors more commonly.
You can connect surround sound channels or stereo headphones through these sockets.
Ideally, in the majority of computers found today there is a 6 connector system included in them for connecting audio out and a microphone as well.
Each of the 6 connectors is color coded as Blue, Pink, Lime, Orange, Grey and Black. These 6 connectors can be used for a surround sound arrangement of up to 8 channels.
A common audio interconnect used in the home media is the Sony/Philips Digital Interface Format or S/PDIF.
These surround sound ports support digital audio and can transmit signals through a TOSLINK or Toshiba Link connector that has optical fiber or through a standard coaxial RCA audio cable.
Most of the computers and home entertainment systems today come with S/PDIF ports.
However, the TOSLINK ports are most commonly used digital audio ports used in systems that support 7.1 channel surround sound arrangement, and it needs just one single cable for that.
The traditional video ports are the VGA ports. The VGA ports or Video Graphics Array connectors typically come with 15 holes in them and are used to connect the monitor or computer display to the video card.
These ports are pretty similar to the serial port connectors but these have holes in them in place of the pins that the serial ports have.
These VGA ports are found in several computers even today and in projectors, High Definition or HD TVs, and in video cards.
There is a D-Sub connector that comprises 15 pins in 3 rows and is typically called DE 15.
The VGA ports are typically the key interface between an older CRT monitor and a computer.
However, the modern LCD and LED monitors also support VGA connectivity but the quality of picture is usually very low.
This is because a VGA pot can normally support analog video signals of up to a resolution of 648 X 480 pixels.
Over time, with the increase in the use and demand for digital video, the VGA ports started to fade out gradually being replaced by Display Ports and HDMI or High Definition Multimedia Interface ports.
However, there are a few laptops that come with a VGA port on-board in order to allow the user to connect the laptop to an external monitor or projector.
Then it was the DVI ports. A DVI or Digital Video Interface port is used to connect LCD monitors with flat panels to the high-performance video graphics card of the computer.
DVI is considered to be a high speed digital interface and was designed to transmit seamless digital video signals without any losses so that it can replace the analog VGA technology.
Generally there are three kinds of DVI connectors designed depending on the type of signals they carry.
These are DVI-I, DVI-D and DVI-A ports. The DVI-I is a specific type of DVI port that can support both analog and digital signals while DVI-D ports can support only digital signals and the DVI-A ports support only analog signals.
The digital signals can be divided further into two types such as single link or dual link.
The single link signal supports a digital signal of up to a resolution of 1920 X 1080 pixels while in comparison a dual link signal can support a digital signal of up to a resolution of 2560 X 1600 pixels.
A DVI port can be a Mini DVI port or a Micro DVI port. A Mini DVI was developed by Apple with an intention to replace the Mini VGA port.
It is physically quite similar but is quite smaller than a standard DVI port. It comes with as many as 32 pins and when these Mini DVI ports are used with the right kind of adapters, these can transmit different types of video signals such as DVI, VGA, composite, and S-Video signals.
The Micro DVI ports, on the other hand, are physically smaller in comparison to the Mini DVI ports just as their name indicates.
However, the Micro DVI ports can transmit only digital signals. You can connect a Macro DV port to any external peripheral device that comes with a VGA and DVI interfaces by using respective adapters.
A DisplayPort is an interface for digital display that may also have optional multiple channel audio and other types of data.
These ports were developed with an intention to replace the VGA ports and the DVI ports to be the key interface between a monitor and a computer.
There are different versions of this port and the latest DisplayPort 1.3 can support a resolution of up to 7680 X 4320 pixels in spite of having just 20 pins which is quite low as compared to the DVI ports.
There is also a Mini DisplayPort version introduced by Apple which has 20 pins with a slightly different layout and a smaller physical size.
Today, most of the laptops come with a Mini DisplayPort as an added video out option apart from HDMI.
The RCA connectors can transmit stereo audio as well as composite video signals using three cables.
Analog video signals are transmitted as composite video and the connector is indicated in yellow color.
The video signals are carried over one channel along with the synchronization pulses of the lines and frames at a maximum standard resolution of 576i.
The red and white connectors typically carry stereo audio signals where the red connector is usually for the right channel and white connector for the left channel.
Component video ports:
Component video interface is where the video signals are divided into more than two channels.
Typically, the quality of the video signal is much better in comparison to composite video.
However, very much like composite video, the component video also transmits only video signals and you will need two separate connectors for the transmission of the stereo audio signals.
The component video ports can transmit both analog and digital video signals.
The three connectors used in component video are colored green, blue and red.
The S-Video connector where ‘S’ stands for ‘Separate’ is a port that is used to carry only video signals.
The quality of the picture in this case is much better in comparison to the composite video but the resolution of the picture is quite less than the component video.
You will typically find an S-Video port present in almost all computers and in all TVs today.
These ports are usually black in color and look pretty much like the PS/2 ports but these have only 4 pins.
Out of these 4 pins, one carries the intensity signals and another carries the color signals. There are respective ground pins for both these pins.
HDMI or High Definition Media Interface ports are digital interfaces that allow connecting High Definition and Ultra High Definition peripheral devices such as monitors, HDTVs, gaming consoles, Blu-Ray players, High Definition Cameras and more.
These ports can transmit uncompressed video signals as well as compressed or uncompressed audio signals.
These connectors usually have 19 pins.
The HDMI 2.0, the latest version of these ports, can support up to 32 audio channels and can carry digital video signals of up to a resolution of 4096 × 2160 pixels with a data bandwidth of up to 18 GB/s.
The modern graphics cards such as the Nvidia RTX 3090 come with at least a couple of these ports.
The Mini HDMI port refers to the HDMI 1.3 version, which has a port and connector combination.
It is much smaller in size as compared to any regular HDMI port.
These ports however have the same 19 pins and are suitable to use in laptops, camcorders, and cameras, but unfortunately these ports are not that popular.
The HDMI 1.4 version is called the Micro HDMI port.
This port also has 19 pins but the layout of these pins is different as compared to the Mini and regular HDMI ports.
Due to their smaller size, these ports are used in devices in which including a regular HDMI port is difficult such as small cameras and single board computers like Raspberry Pi 4. These ports resemble a micro USB port to some extent.
The USB ports, a short for Universal Serial Bus ports, can connect almost any type of peripheral device to a computer that comes with USB connectivity.
These are external hard disk, mouse, keyboard, printer, scanner, and others. These ports were introduced in 1997 and are most commonly used ports today.
The computers usually come with two USB ports but depending on the model there can be more than that.
These USB ports can carry data at a speed of 12 mbps or megabits per seconds and a few USB ports can even charge a USB compliant device.
The USB ports have replaced the serial ports, parallel ports, game ports, power chargers, and PS/2 connectors in the portable devices.
These ports are very versatile and can act as an interface to connect external peripherals to a computer and as a means to transfer data and even use it as a power supply for the external devices connected to these ports.
There are different kinds of USB ports available.
The commonly used one is the USB 3.0 port that can support a data rate of up to 400 Mbps.
The USB 3.1 ports however support a much higher data rate than that which is up to 10 GB/s.
The latest spec of the USB ports is the USB Type C port which is actually a reversible connector.
These ports are considered to be future proof and replace all other types of USB ports. This latest version of USB ports come with 24 pins.
There is also a USB 4 port which is typically an USB-C only port which means you can connect only USB Type C devices to it and it can support a data rate of up to 40 GB/s.
As said earlier, these USB ports can charge devices connected to it due to the USB Power Delivery specs.
The USB Type C ports can provide 5 amp current at 20 volts, courtesy the latest Fast Charging Technology.
This means that the USB Type C ports can provide up to 100 watts of power which is enough to charge a laptop or a smartphone battery to its full capacity in quick time.
The Ethernet port connects a computer to high speed internet or one computer to another to form a network using the network cable.
The Ethernet port typically resides on an Ethernet Card and can carry data at a speed ranging between 10 megabits per second and 1000 megabits per second, depending on the bandwidth of the network.
Technically speaking, Ethernet is actually a specific networking technology which allows you to connect your computer to the internet or with other computers and communicate with them thereby creating a computer network.
In this case, the interface used for creating the computer and telecommunications network is called the Registered Jack or RJ 45 port.
This is especially used for Ethernet connectivity over cable connections.
The RJ 45 connector comes with 8 pins and acts as an 8P – 8C type modulator connector.
These ports often come with LED lights that indicate data transmission and packet activity.
The latest Ethernet technology, which is most commonly referred to as Gigabit Ethernet, supports a high data transfer rate of up to 10 Gigabits per second.
There is also another type of Registered Jack called the RJ 11 which is typically used as an interface to make modem, telephone and ADSL or Asymmetric Digital Subscriber Line connections.
However, the computers as of now are usually not equipped with an RJ 11 port but it is extensively used in the telecommunications sector.
The RJ 11 port looks pretty much the same as the RJ 45 port but is actually a bit smaller in size having just 6 pins in it.
The e-SATA or the External Serial Advanced Technology Attachment connector is used to connect external mass storage devices.
The modern eSATA connectors are more powerful and are called e-SATAp or Power eSATA ports.
These ports are hybrid in design and therefore can support both USB and eSATA connectivity.
However, the e-SATAp ports are not yet approved by the SATA organization or by the USB organization.
Therefore, users may use it at their own risk.
There may also be a Secure Digital or SD card reader or micro SD card reader port embedded on the computers and laptops.
These cards help in transferring data. The micro SD card reader port can usually be found in smartphones and cameras.
This is a technology that was developed jointly by Intel and Apple in 2011. These ports are pretty powerful and serve different purposes apart from transferring data at a high speed.
The most unique aspect of these ports is that you can use these ports in other ports as well.
This means that a single port can have two different uses. The Thunderbolt port can be easily identified by its unique Thunder logo and supports only those devices that are Thunderbolt compatible.
Typically, every Apple laptop comes with a Thunderbolt port and most other computers have it in them as well.
There are three different versions of Thunderbolt ports.
The Thunderbolt 1 port is faster than a USB 3.0 port and supports a data transfer rate of up to 10 GB/s.
The Thunderbolt 2 port is backward compatible and supports a data transfer rate of up to 20 GB/s and a 4K Video monitor.
And, the Thunderbolt 3 port is the fastest port in the market with a data transfer rate of up to 40 GB/s and can support two 4K monitors at the same time.
The Thunderbolt 3 port is also compatible with the USB Type C connector and is used for computer networking.
A computer uses different types of ports and protocols to communicate and transfer data and information with the peripheral devices connected to it.
Thanks to this article now you know everything about all the ports and their characteristic features with uses.