Your computer has physical ports that you see and plug into, such as USB devices. And there are also software ones that exist in the virtual electronic digital world and are inaccessible to the naked eye. However, knowledge about them will not hurt you at all, since they are directly related to computer security issues. This means that we will try to provide such knowledge in the simplest and most intelligible form possible.

What is a software port

As you probably already know, computers tend to exchange data. All those electromagnetic pulses moving through wires, optical fibers, flying in the air (3G, Wi-Fi, Bluetooth), pumped through space communications satellites, must arrive somewhere. Into some programs for subsequent processing and display of results on the display. Or to save something to disk.

This means that programs must be ready to transmit and receive electronic information. Therefore, ports are allocated for them within the operating system - means of exchanging information. This is one of the few cases in the formation of digital terminology when the term is not abstruse and accurately describes the essence of the phenomenon. A seaport receives and dispatches ships, an airport receives airplanes, and a computer port receives data packets.

Everyone feels comfortable when port usage is organized. This is done by the IANA organization (which stands for Internet Assigned Numbers Authority). Which, in turn, is controlled by the ICANN office, which manages domains.

So, the role of only 1024 ports is strictly regulated. For example, the 80th is at the disposal of browsers. For an encrypted connection - 443. To connect via SSH - 22nd. And so on.

How it works

“Yeah!” - the server on which the site is located thinks, “the user has requested a web page! This means, according to IANA standards, I must send a document via TCP/IP to port 80. Through it, the browser will accept everything and immediately display it on the screen.”

“Here comes the arrival of the packages with the page!” - the browser rejoices, receiving data on port 80. - “So it’s time to get to work! Now I’ll draw everything on the display!”

“Wait a minute!” - the newly launched Thunderbird email client says, “What about me? I need to connect to the mail server!” But he calms down, because the standard port for the IMAP protocol is 993, which is immediately provided without any questions asked. And to send letters using a secure, encrypted connection - 465.

(Without encryption, using SMTP protocol on port 25, you are not sending anything, especially in open networks Wi-Fi, right? Otherwise, your letters and passwords would cry bitter tears, falling into the wrong hands.)

In general, there are enough ports for all applications that want to establish any connections. But whether everyone should be allowed to do this is already a question of security.

Safety

So, for programs running on the network, virtual ports are allocated for the purpose of establishing connections. These connections are:

1. incoming, initiated from outside via open ports;
2. outgoing, initiated by software on the computer itself.

When a port is open but not in use or in standby mode, it is said to be “listening.” For example, a torrent client waits until someone connects and starts downloading data, constantly keeping something in the range 6881-6889 ready.

Each server also has at least one open port Yes, otherwise no one will be able to connect.

Skype usually uses port 36000 for incoming connections. If nothing incoming is received, then it will be impossible to reach you.

The ICQ client works in exactly the same way, which in the Windows version has already become an analogue of Skype, having learned to make calls and make video calls.

So, a bad person uses special software to scan ports, finds an open one and breaks into your computer. It can steal some data and load malicious programs into Windows.

Network worms (a type of virus) are able to enter automatically, infecting all copies of Windows on all computers that they manage to reach.

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Last edit: 2012-09-10 06:41:11

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Why do you have all the system units under the tables in your classroom?
- And I like to watch how students are looking for a USB port.

The information input/output system, along with the processor and memory, is one of the most important computer systems. And the I/O ports located in the system unit are the most important part of the architecture personal computer.

Purpose and types of I/O ports

The term “port” came into the computer lexicon from circuit design. In it, an I/O port is any hardware solution that allows any controller or processor to exchange information with I/O devices directly, bypassing memory. For example, in the popular AVR family of microcontrollers, ports are called contacts that allow you to exchange data with external devices.

In relation to PC architecture, I/O ports can be called connectors that allow you to connect peripheral devices to the computer, as well as microcircuits that serve these connectors.

The purpose of I/O ports is to transmit and receive information outside the computer. Various devices responsible for receiving, processing, transmitting and converting information into a form convenient for user perception can be connected to the I/O ports.

In this article, we will not touch on ports that can be found exclusively on expansion boards, but will briefly talk only about the functions and features of the ports, which are most often found on the motherboard itself.

List of I/O ports commonly used in a personal computer:

• Parallel (LPT)
• Serial (COM)
• Game
• Ethernet connector
• PS/2 connector (mouse)
• PS/2 connector (keyboard)
• VGA connector and other video outputs
• Audio connectors for connecting speakers, microphone, etc.

ATX motherboard panel showing I/O ports

I/O ports on an ATX form factor motherboard:

1 – PS/2 connector (mouse); 2 – PS/2 connector (keyboard); 3 – Ethernet output; 4 – Two USB connectors; 5 – Serial port connector; 6 – Parallel port connector; 7 – VGA connector; 8 – Game port; 9 – Audio ports (from left to right: line out, input, microphone).

Often in computer usage, PC I/O ports include only traditional, low-speed I/O ports that existed in the first IBM-compatible computers - these are parallel, serial and game ports. It should be noted that on motherboards On modern computers, these ports are rare.

The main feature of a parallel port is the simultaneous transmission of data over several lines. This feature brings LPT closer to the internal buses of a computer. The main purpose of the parallel port is connections external devices, and in most cases this device is a printer.

The first versions of the parallel port were unidirectional, that is, data through the cable could only be transmitted in one direction - to the peripheral device. Subsequently, improved LPT interface standards were introduced, in which data could be transferred in both directions.

Serial port (COM)

This port features serial data transmission over a single line. Serial transmission means that bits of information are transmitted over the line one after another. In addition, data transmission on the serial port is bidirectional. Typically, COM is used to connect peripherals such as a mouse or modem. The port connector on the computer motherboard uses a 9-pin DE-9 male connector.

Game port

Today this port is not very often found on motherboards. In addition, it is not supported by modern OS, such as Windows 7. However, it can still be seen on sound cards. The port connector is a 15-pin connector.

As you can guess from the name of the port, it is intended primarily for connecting joysticks. A special feature of the port is the ability to connect two devices to it at once. In addition, in sound cards, the game port is often used to connect MIDI devices, such as synthesizers. Since it is capable of working with analog and analog-to-digital devices, an analog-to-digital converter is built into the microcircuit that serves it.

PS/2

The PS/2 connector is used on a computer to connect a mouse and/or keyboard. Despite the fact that it was developed quite a long time ago, back in the mid-1980s, nevertheless, it is still actively used in computers. Some motherboards have two universal connectors to which you can connect both a mouse and a keyboard, while others have two separate connectors for a mouse and a keyboard. The green connector is for connecting a mouse, the blue connector is for a keyboard. Both connectors are made in mini-DIN format with 9 pins.

USB

The USB port, which will be discussed in detail in a separate article, is the fastest, most versatile and productive I/O port in modern computers. It is for this reason reason USB practically replaced many other ports. Typically, a computer has several connectors for connecting USB devices.

Conclusion

I/O ports of a personal computer are an integral part of its system I/O and are designed for connecting various peripheral devices. The presence of I/O ports allows the user to enter information into the computer, receive it from other computers and devices, and transfer it.

– these are connectors used to connect various peripheral devices to the system unit. Connectors for computer ports are located on the back and front panels, and in laptops they are located on the sides of the case.

The name “port,” as applied to a computer, is borrowed from electronics, where an input-output port is the hardware for data exchange between the controller (or processor) and the connected device. Likewise in a computer, ports receive and transmit information from a device located outside system unit.

Any computer has a minimum set of computer ports, without which it will not function fully. It is necessary to connect , and , to the system unit, otherwise it will not be a computer, but an expensive iron box. If necessary, computer ports can be increased using expansion cards connected to. Let's look at the set of ports that are always present in an ordinary computer.

Minimum set of ports on a computer

Depending on the manufacturer of the system unit, its age and purpose, the number of ports varies, but almost always there will be connectors such as:

1. Ports that accept a mouse and keyboard, called PS/2 ports. Nowadays, computers are increasingly being manufactured without these connectors or with one combined for connecting both a keyboard and a mouse. At the moment, the PS/2 port is obsolete; you can connect a mouse and keyboard in USB port.
2. Port connector for connecting a monitor.
3. RJ-45 connector used for network connection (the local network or Internet).
4. USB ports that are universal.
5. Audio connectors of the sound card. A microphone, speakers or headphones, and a line input are connected here.

Most of the connectors are already on the computer's motherboard. In cases where any connector is missing, external devices can be connected via universal ports.

Universal computer ports

Serial port

One of the oldest universal ports, developed at the beginning of the evolution of computers. It is a 9 or 25 pin (less common) connector called a COM port (or serial port). The transmission of information in it occurs in one stream, sequentially one after another, which determined its name. In the most early computers a modem or a mouse was connected to it, but now it is rarely used anywhere, because... it has gradually been replaced by the USB port.

Parallel port

This is another rarity from the beginning of the computer era. It is called LPT - port or parallel computer port. At first it was developed for connecting, and then they began to connect other devices. Information through the LPT port is transmitted over several streams, which is reflected in the name “parallel port”. The parallel port has 25 pins, which is why it can be confused with a 25-pin serial port. However, there is a big difference between them: the LPT port is equipped with contacts in the form of holes, and the serial port has contacts in the form of plugs. Differs like dad from mom.

Universal USB computer port

Currently, old ports are being replaced by more powerful universal ports, one of which is USB. It appeared in the mid-90s of the last century and continues to develop to this day. The transfer of information here occurs sequentially, as in COM port, but the speed of its transmission is much higher. Most peripheral devices are connected via a USB port. For example, the one we are all familiar with connects directly to the USB port. USB connectors are located on the rear and front panels of the system unit.

Modern computers are equipped with 2 types of USB connectors: USB 2.0 and USB 3.0, which are compatible with each other, but differ in data transfer speed. USB 3.0 transfers information faster than USB 2.0. You can distinguish them by the color of the connector: USB 3 is blue or red.

In addition to the ports discussed above, there are also such universal high-speed ports as FireWare and eSata. For a novice user they are not of interest, because... their scope of application lies in professional computers, and even then they are increasingly being replaced by USB connections.

Monitor connectors

The connectors for connecting a monitor are located on the rear panel of the system unit and, depending on yours, may have one form or another.

VGA video card connector

This is one of the oldest and most common monitor connectors. It got its name from the abbreviated English Video Graphics Adapter - video graphics adapter. Motherboards with a built-in video card are most often equipped with this connector. The maximum resolution of the transmitted signal is 1280x1024 pixels.

DVI video card connector

A more advanced connector compared to VGA due to the ability to transmit the monitor signal directly in digital form, without additional conversions, unlike VGA, in which video is transmitted in analog format. Digital video transmission is not subject to interference, which has a positive effect on image quality. To connect a monitor via DVI output, it must also have a corresponding connector. The maximum resolution of the transmitted signal is 2560x1600 pixels.

HDMI video card connector

Another connector for high quality digital connection monitor, as its name suggests - High Definition Multimedia Interface. The HDMI port is significantly smaller in size compared to DVI, and is also capable of transmitting high-quality multi-channel audio. The maximum resolution of the transmitted signal is 2560x1600 pixels. Audio cards have 3 connectors colored green, blue and pink. Green color is a linear output for connecting speakers or headphones, a linear input for inputting sound from another source, a microphone is connected to the pink connector.

Expensive multi-channel audio cards have more connections and, in addition to the color marking of the connectors, they always add labels to designate the ports, thanks to which the correct connection of the audio system will not be difficult.

This article discusses the most common computer ports, which are required in any system unit. Actually there is more a large number of other ports used in any professional areas, and they are unlikely to be of interest to a novice user.

Share.

Port - a connector for connecting an external device to a computer adapter, as well as a logical address used by the processor to access various devices. Communication ports are used to connect a computer and external devices such as a mouse, printer, keyboard, etc. Various measuring instruments and sensors are often connected to the ports. There are two types of ports - serial (serial ports) and parallel. Since any device can interact with a computer through them (provided that it supports the port protocol), both parallel and serial ports are also called universal. External devices connected to serial ports are said to have a “serial” interface, and those connected to parallel ports are said to have a “parallel” interface. All ports can be configured for a given speed of transmission and reception of information.

Majority desktop computers have two serial ports, called COM1 and COM2 for connecting external devices, ports COM3, COM4 for devices built inside the system unit, but you can install a larger number of serial ports. Serial ports are traditionally connected to a modem and a mouse. Serial ports are called serial ports because they transmit information sequentially bit by bit. The maximum data transfer rate via the serial port is 115 kb/s. Currently this port superseded (not only from use, but also from the “boards” of some motherboards) by such successors of the modern IT industry as USB and FireWire.

In addition to serial ports, a computer usually has parallel ports - LPT. Through such a port, the computer can send a group of bits of information to the device at the same time. The printer is usually connected to a parallel port. Printers, plotters, scanners, communication devices and data storage devices, as well as electronic keys are connected to LPT ports. Sometimes a parallel interface is used for communication between two computers - a network is obtained. The LPT port can operate in one of the following modes:

Standard Parallel Port (SPP). Standard, as the name suggests, parallel port operating mode; The following variations expand the functionality of the parallel port:

Nibble Mode. A mode that allows the LPT port to operate in duplex (from PC to device and vice versa) and at the same time SPP mode of operation;

Byte Mode. A very rare mode of data transmission via a parallel port;

Enhanced Parallel Port (EPP). The added functionality provides bidirectionality and a data transfer rate of 2 Mb/s;

Extended Cababilities Port (ECP). There is now the possibility of hardware data compression, the use of DMA mode, a buffer has been added;

USB bus ports were first discovered as part of a computer in 1996 and have so far managed to evolve quite widely, having grown several branches from the original standard. Today there are four versions of this tire. Nowadays there are already plenty of devices with a USB interface. The bus allows you to connect devices remote from the computer at a distance of up to 25 m (using intermediate hubs). The USB pin is aimed at peripheral devices connected to a PC. USB enables data exchange between the host computer and a variety of peripheral devices (PUs). Each device on the USB bus (there can be up to 127 of them) automatically receives its own unique address when connected. Logically, the device is a set of independent endpoints with which the host controller (and client software) exchanges information.

Basic descriptive characteristics of a computer.

System unit

The system unit is the main unit, inside which the most important components are installed. Devices located inside the system unit are called internal, and those connected to it from the outside are called external and peripheral. The main characteristic of the system unit case is a parameter called form factor. The requirements for the devices being placed depend on it. The form factor of the system unit must be consistent with the form factor of the main (system, motherboard) board. Currently, the most common cases are with the ATX form factor. The cases are supplied with a power supply.

Internal devices of the system unit.

-Motherboard - the main board of the computer. It contains:

CPU - the main chip that performs arithmetic and logical operations- the brain of the computer. The processor consists of cells similar to RAM cells, but in these cells data can not only be stored, but also changed. The internal cells of the processor are called registers. Some registers are co-and registers, that is, those that perceive data as commands that control data processing in other registers. By controlling the sending of data to different registers, you can control the processing of data. The execution of programs is based on this. The processor is connected to other devices by several groups of conductors called buses. There are three main buses: data bus, address bus and command bus. The address bus consists of 32 parallel conductors (32-bit). It transmits the addresses of RAM cells. A processor is connected to it to copy data from the OP cell into one of its registers. The copying itself occurs via the data bus. In modern computers, it is usually 64-bit, i.e. 8 bytes are received for processing at the same time. Commands are transmitted via the command bus from the area of ​​the operating system in which the programs are stored. Most modern computers have a 32-bit command bus, but there are also 64-bit ones.

The main characteristics of the processor are the bit capacity, clock speed and cache memory. Bit capacity indicates how many bits of information the processor can process at one time (one clock cycle). Clock frequency determines the number of cycles per second, for example, for a processor performing about 3 billion cycles per second, the clock frequency is 3 GHz/sec. Data exchange within the processor occurs faster than with RAM. In order to reduce the number of accesses to the OP, a buffer area is created inside the processor - cache memory. Receiving data from the OP, the processor simultaneously writes it to the cache memory. During subsequent access, the processor looks for data in the cache memory. The larger the cache memory, the faster the computer runs.

microprocessor kit (chipset) - a set of chips that control the operation internal devices and defining the main functionality of the motherboard.

tires - sets of conductors through which signals are exchanged between internal devices.

RAM - a set of chips designed for temporary data storage

RAM (RAM - random access memory) - an array of cells capable of storing data. memory can be dynamic and static. Dynamic memory cells can be thought of as microcapacitors that accumulate electrical charge. Dynamic memory is the main RAM of a computer. Static memory cells are triggers - elements that store not a charge, but a state (on/off). This type of memory is faster, but also more expensive and is used in the so-called. cache memory designed to optimize processor performance. RAM is located on standard panels (modules, rulers). The modules are inserted into special connectors on the motherboard.

ROM - read only memory device. When the computer is turned on, its RAM is empty. But the processor needs commands to start working. Therefore, immediately after switching on, the start address is set on the address bus. This happens in hardware. This address points to the ROM. ROM contains “hardwired” programs that are written there when ROM chips are created and form the base input/output system (BIOS - Base Input/Output System). The main purpose of this package is to check the composition and functionality of the basic computer configuration and ensure interaction with the keyboard, monitor, hard drive and a floppy drive.

connectors for connecting additional internal devices (slots).

HDD.

HDD- a device for long-term storage of large amounts of data and programs.

In fact, it is not one disk, but a group of disks that have a magnetic coating and rotate at high speed. A read-write head is located above the surface of each disk. At high rotation speeds, an aerodynamic cushion occurs between the surface of the disk and the head. When the current flowing through the head changes, the magnetic field strength in the gap changes, which causes a change in the magnetic field of the ferromagnetic particles that form the coating of the disk. This is how you write to disk. Reading occurs in reverse order. Magnetized particles induce a self-induction emf in the head, electromagnetic signals arise, which are amplified and transmitted for processing. The operation of the hard drive is controlled by a special device - a controller. hard drive. The controller functions are partially built into HDD, and are partially located on chipset chips. Certain types of high-performance controllers are supplied on a separate board.

Floppy drive.

To quickly transfer small (up to 1.4 MB) amounts of information, floppy disks are used, which are inserted into a special drive - drive.

CD or DVD drive .

The operating principle of a CD device is to read (write) data using a laser beam reflected from the surface of the disk. At the same time, the recording density, compared to magnetic disks, is very high. A standard CD can store up to 650MB. The advent of the DVD format marked a transition to a new, more advanced level in the field of storage and use of data, sound and video. Initially, the abbreviation DVD stood for digital video disc, which is optical discs with large capacity. These disks are used to store computer programs and applications, as well as full-length films and high-quality sound. Therefore, the abbreviation DVD, which appeared a little later, was deciphered as digital versatile disc, i.e. a universal digital disk is more logical. Outside, DVDs look like regular CD-ROM discs. However, DVD has much more possibilities. DVDs can store 26 times more data than a regular CD-ROM. Having physical dimensions and appearance Like a regular CD or CD-ROM, DVDs represent a huge leap in storage capacity over their ancestor's 650MB storage capacity. A standard single-layer, single-sided DVD disc can store 4.7GB of data. But this is not the limit - DVDs can be produced using a two-layer standard, which allows you to increase the capacity of data stored on one side to 8.5GB. In addition, DVDs can be double-sided, which increases the capacity of one disc to 17GB.

Video card

Together with the monitor, the video card forms the computer's video system. The video card (video adapter) performs all operations related to controlling the monitor screen and contains video memory in which image data is stored.

Sound card.

The sound card performs operations related to processing sound, speech, and music. The sound is played through speakers (headphones) connected to the output sound card. There is also a connector for connecting a microphone. The main parameter of the audio signal is the bit depth. The higher the bit depth, the smaller the error associated with digitization, the better the sound.

Peripherals

Peripheral devices are connected to computer interfaces and are designed to perform auxiliary operations. By value. Peripheral devices can be divided into:

data input devices:

Keyboard is a symbolic data input device.

Mouse - command control device

Scanners, tablets (digitizers), digital photos and video cameras - devices for entering graphic data

data output devices:

-Printers:

Laser. Provide high print quality and high speed.

Jet. The main purpose is color printing. They are superior to laser ones in terms of quality/price.

storage devices:

Flash drives. A data storage device based on non-volatile flash memory. It has minimal dimensions and allows for hot plugging via a USB connector, after which it is recognized as a hard drive. The volume of a flash drive can range from 32 MB to several GB.

data exchange devices:

Modem. A device designed to exchange information between remote computers via communication channels. Depending on the type of channel, modems are divided into radio modems, cable modems, etc. The most common modems are for telephone lines.

Not all devices that we need are already connected to the computer in its case. There are a number of devices that need to be connected during operation or added to expand functionality; without many of them, working with a computer is impossible. Such devices include USB flash drives, printers, mice, keyboards, external hard discs, speakers and much more. All this is connected through device connection interfaces to the computer.

External ports are an interface or point of interaction between a computer and another peripheral device. The main purpose of such ports is to provide a connection point for the device cable to transmit and receive data from the central processor. In this article we will look at what external computer ports are, and also look at the main ports and their purpose.

External connectors on a computer are also called communication ports, as they are responsible for communication between the computer and peripheral devices. Typically, the base of the port is located on the motherboard.

All external computer interfaces are divided into two types, depending on their type and the protocol used to communicate with the central processor. These are serial and parallel ports.

A serial port is an interface through which devices can be connected using the serial protocol. This protocol allows one bit of data to be transmitted at a time over a single line. The most common type of serial port is D-sub, which allows RS-232 signals to be transmitted.

The parallel port works a little differently, data exchange between the peripheral device is carried out in parallel using several communication lines. Most ports for modern devices- parallel. Next we will look in more detail at each type of external computer interfaces, as well as their purpose.

Input and common ports

In modern computers, serial ports are practically no longer used; they have been replaced by more modern parallel ports, which have better performance. But many motherboards still have connectors for these interfaces. This is done for compatibility with older devices such as mice and keyboards.

PS/2

The PS/2 connector was developed by IBM to connect a mouse and keyboard. It began to be used since the IBM/2 personal computer. The name of the port was derived from the name of this computer. The interface has special markings - purple for the keyboard and green for the mouse.

As you can see, this is a six-pin connector, here is its diagram:

Even though the bases and pin layouts for the mouse and keyboard are the same, the computer will not detect the device if you plug it into the wrong connector. As I already said, at the moment PS/2 has already been supplanted by another technology. Nowadays, connecting peripheral devices to a computer is most often done via USB.

Serial Port

Despite the fact that serial ports are called whole group ports, including PS/2, there is another meaning for this term. It is used to designate an interface compatible with the RS-232 standard. Such interfaces include DB-25 and DE-9.

DB-25- This is a variant of the D-Sub connector originally developed as the main port for connecting via the RS-232 protocol. But most devices don't use all the pins.

Then it was developed DE-9, which worked using the same protocol, and DB-25 began to be used more often to connect a printer instead of a parallel port. Now DE-9 is the main serial port operating using the RS-232 protocol. It is also called COM port. This connector is still sometimes used to connect mice, keyboards, modems, IBLs and other devices that use this protocol.

Nowadays, DB-25 and DE-9 interfaces for connecting devices to a computer are used less and less, because they are being replaced by USB and other ports.

Centronics parallel port or 36-pin port

The Centronics or 36-pin port was designed to connect a computer and a printer using a parallel protocol. It has 36 pins and before starting wide application USB was quite popular.

Audio ports

Audio ports are used to connect speaker systems and other audio output devices to the computer. Audio signals can be transmitted in analog or digital form, depending on the connector used.

3.5 mm jack

This port is most commonly used to connect headphones or surround sound devices. The connector consists of six sockets and is available on any computer for audio output, as well as connecting a microphone.

The nests are color coded as follows:

S/PDIF/TOSLINK

Sony/Phillips Digital Audio Interface is used in various playback devices. It can be used for coaxial RCA audio cable and fiber optic TOSLINK.

Most home computers contain this connection interface via TOSLINK (Toshiba Link). This port can support 7.1 channel surround sound with just one cable.

Video interfaces

VGA port

Most computers have this port. It is located on the video card and is designed to connect screens, projectors and high-definition TVs. This is a D-Sub type port, consisting of 15 pins arranged in three rows. The connector is called DE-15.

The VGA port is the primary interface for communication between computers and older CRT monitors. Modern LCD displays and led monitors support VGA, but the image quality is reduced to 648x480 resolution.

Due to the increasing use of digital video, VGA ports are being replaced by HDMI and Display. Some laptops also have VGA ports for connecting external monitors. Here is his diagram:

Digital Video Interface (DVI)

DVI is a high-speed digital interface for providing communication between a video card and a computer screen. It was designed to minimize video signal transmission losses and replace VGA technology.

There are several types of DVI connectors, these are DVI-I, DVI-D and DVI-A. DVI-I is a port capable of transmitting both digital and analog signals. DVI-D only supports digital signals, DVI-A only supports analog signals. Digital signals can transmit video with a resolution of 2560x1600.

In addition, several modifications have been developed. Apple has developed Mini-DVI, which looks very similar to VGA and is much smaller than regular DVI:

Then there was Micro-DVI, it is even smaller than Mini-DMI and is similar in size to a USB connector and is capable of transmitting only digital signals:

Display Port

Display Port is a digital interface that was designed to replace VGA and DVI and can transmit not only video, but also audio signals. The latest version can transmit video with resolutions up to 7680x4320.

Display Port has a 20-pin connector that is much smaller than DVI and allows for higher video resolutions. Here is the contact layout:

RCA connector

The RCA port can transmit audio and video signal using three cables. The video signal is transmitted via a yellow cable and supports a maximum resolution of up to 576i. Red and white port are used to transmit audio signal.

Component Video

The Component Video interface splits the video signal into multiple channels and produces higher quality than RCA. Both analog and digital signals can be transmitted.

S-Video

S-Video is used only for video transmission. The image quality is better than the previous two options, but the resolution is lower than in Component. This port is usually black and is found on all televisions and most computers. It is very similar to PS/2, but has only 4 pins:

HDMI

HDMI stands for High Definition Media Interface. This is an interface for transmitting and receiving high-definition digital video and audio signals to devices such as computer monitors, high-definition TVs, Blue-Ray players, game consoles, and cameras. Now HDMI is considered standard port for transmitting video data.

An HDMI Type A port looks like this:

The connector uses 19 pins, and latest version 2.0 can transmit a video signal with a resolution of 4096x2160 and 32 audio channels. Contact connection diagram:

USB

The Universal Serial Bus (USB) interface has replaced serial and parallel ports, PS/2 game ports and charging device. This port can be used for data transfer, act as an interface for connecting peripheral devices, and even be used as a power source. Now there are four types of USB: Type-A, Type-B, Type-C, micro-USB and mini-USB. Using any of them, external devices can be connected to a computer.

USB Type-A

The USB Type-A port has a 4-pin connector. There are three different, compatible versions - USB 1.1, USB 2.0 and USB 3.0. The latter is a common standard and supports data transfer rates of up to 400 Mbit/s.

Later, the USB 3.1 standard was released, which supports speeds up to 10 Gbps. Black indicates USB 2.0, while USB 3.0 is labeled in blue. You can see this in the image:

Contact connection diagram:

USB Type-C

Type-C is the latest USB specification and the connector can be inserted into this connector in any direction. It is planned that over time it will replace Type-A and Type-B.

The Type-C port consists of 24 pins and can carry current up to 3A. This feature is used for modern fast charging technology.

Network ports

RJ-45 port

The RJ-45 interface is used to connect a computer to the Internet using Ethernet technology. The Registered Jack (RJ) interface is used to organize computers. RJ-45 is an 8-pin modular connector.

The latest version of Ethernet is called Gigabit Ethernet and supports data transfer rates of up to 10 Gbps. RJ-45 is usually called a LAN Ethernet port with connection type 8P – 8C. Often ports are equipped with two LEDs to indicate packet transmission and reception.

As I already said, RJ-45 has 8 pins, they are shown in this diagram:

RJ-11

RJ-11 is another type of Registered Jack that is used as an interface for a telephone, modem, or ADSL connection. Computers are almost never equipped with this, but it is the primary interface for all telecommunications networks.

RJ-45 and RJ-11 are similar to each other, but RJ-11 is slightly smaller and uses 6 sockets and 4 pins (6p-4c) but a 6P-2C circuit would be sufficient. Here is a picture of this connector:

You can also compare how similar RJ-45 and RJ11 are:

HDD

E-SATA

E-SATA is an external Serial AT Attachment port that is used to connect external mass storage devices. The modern E-SATA connector is called e-SATAp and is compatible with E-SATA.

These are hybrid ports that can connect E-SATA and USB. But neither SATA nor USB officially support SATAp, so the user will use them at his own risk.

conclusions

In this article, we looked at external computer interfaces for connecting peripheral devices. All of them were developed at different times and each a new version, usually much better than the other. Do you know or use other external computer ports? Write in the comments!