Computer Port (hardware)
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computer hardware Computer hardware includes the physical parts of a computer, such as the computer case, case, central processing unit (CPU), Random-access memory, random access memory (RAM), Computer monitor, monitor, Computer mouse, mouse, Computer keyboard, ...
, a port serves as an interface between the computer and other computers or peripheral devices. In computer terms, a port generally refers to the part of a computing device available for connection to peripherals such as input and output devices. Computer ports have many uses, to connect a
monitor Monitor or monitor may refer to: Places * Monitor, Alberta * Monitor, Indiana, town in the United States * Monitor, Kentucky * Monitor, Oregon, unincorporated community in the United States * Monitor, Washington * Monitor, Logan County, West ...
,
webcam A webcam is a video camera which is designed to record or stream to a computer or computer network. They are primarily used in videotelephony, livestreaming and social media, and security. Webcams can be built-in computer hardware or peripheral d ...
,
speakers Speaker may refer to: Society and politics * Speaker (politics), the presiding officer in a legislative assembly * Public speaker, one who gives a speech or lecture * A person producing speech: the producer of a given utterance, especially: ** In ...
, or other
peripheral devices A peripheral or peripheral device is an auxiliary device used to put information into and get information out of a computer. The term ''peripheral device'' refers to all hardware components that are attached to a computer and are controlled by the ...
. On the
physical layer In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer; The layer most closely associated with the physical connection between devices. This layer may be implemented by a PHY chip. The ...
, a computer port is a specialized outlet on a piece of equipment to which a plug or
cable Cable may refer to: Mechanical * Nautical cable, an assembly of three or more ropes woven against the weave of the ropes, rendering it virtually waterproof * Wire rope, a type of rope that consists of several strands of metal wire laid into a hel ...
connects. Electronically, the several conductors where the port and cable contacts connect, provide a method to transfer signals between devices. Bent pins are easier to replace on a cable than on a connector attached to a computer, so it was common to use connectors for the fixed side of an interface. Computer ports in common use cover a wide variety of shapes such as round ( PS/2, etc.), rectangular (
FireWire IEEE 1394 is an interface standard for a serial bus for high-speed communications and isochronous real-time data transfer. It was developed in the late 1980s and early 1990s by Apple in cooperation with a number of companies, primarily Sony an ...
, etc.), square (
Telephone plug A telephone jack and a telephone plug are electrical connectors for connecting a telephone set or other telecommunications apparatus to the telephone wiring inside a building, establishing a connection to a telephone network. The plug is inserte ...
), trapezoidal (
D-Sub The D-subminiature or D-sub is a common type of electrical connector. They are named for their characteristic D-shaped metal shield. When they were introduced, D-subs were among the smallest connectors used on computer systems. Description, no ...
— the old printer port was a
DB-25 The D-subminiature or D-sub is a common type of electrical connector. They are named for their characteristic D-shaped metal shield. When they were introduced, D-subs were among the smallest connectors used on computer systems. Description, no ...
), etc. There is some standardization to physical properties and function. For instance, most computers have a
keyboard Keyboard may refer to: Text input * Keyboard, part of a typewriter * Computer keyboard ** Keyboard layout, the software control of computer keyboards and their mapping ** Keyboard technology, computer keyboard hardware and firmware Music * Musi ...
port (currently a Universal Serial Bus
USB Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad ...
-like outlet referred to as USB Port), into which the keyboard is connected. Physically identical connectors may be used for widely different standards, especially on older personal computer systems, or systems not generally designed according to the current Microsoft Windows compatibility guides. For example, a 9-pin D-subminiature connector on the original
IBM PC The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first microcomputer released in the IBM PC model line and the basis for the IBM PC compatible de facto standard. Released on August 12, 1981, it was created by a team ...
could have been used for monochrome video, color analog video (in two incompatible standards), a joystick interface, or for a
MIDI MIDI (; Musical Instrument Digital Interface) is a technical standard that describes a communications protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and re ...
musical instrument digital control interface. The original IBM PC also had two identical 5 pin DIN connectors, one used for the keyboard, the second for a cassette recorder interface; the two were not interchangeable. The smaller mini-DIN connector has been variously used for the keyboard and two different kinds of mouse; older
Macintosh The Mac (known as Macintosh until 1999) is a family of personal computers designed and marketed by Apple Inc., Apple Inc. Macs are known for their ease of use and minimalist designs, and are popular among students, creative professionals, and ...
family computers used the mini-DIN for a serial port or for a keyboard connector with different standards than the IBM-descended systems.


Electrical signal transfer

Electronically, hardware ports can almost always be divided into two groups based on the signal transfer: *Analog ports *Digital ports: **
Parallel port In computing, a parallel port is a type of interface found on early computers (personal and otherwise) for connecting peripherals. The name refers to the way the data is sent; parallel ports send multiple bits of data at once ( parallel ...
s send multiple bits at the same time over several sets of wires. **
Serial port In computing, a serial port is a serial communication interface through which information transfers in or out sequentially one bit at a time. This is in contrast to a parallel port, which communicates multiple bits simultaneously in parallel. ...
s send and receive one bit at a time via a single wire pair (Ground and +/-). After ports are connected, they typically require
handshaking A handshake is a globally widespread, brief greeting or parting tradition in which two people grasp one of each other's like hands, in most cases accompanied by a brief up-and-down movement of the grasped hands. Customs surrounding handshakes a ...
, where transfer type, transfer rate, and other necessary information is shared before data is sent. Hot-swappable ports can be connected while equipment is running. Almost all ports on personal computers are hot-swappable.
Plug-and-play In computing, a plug and play (PnP) device or computer bus is one with a specification that facilitates the recognition of a hardware component in a system without the need for physical device configuration or user intervention in resolving reso ...
ports are designed so that the connected devices automatically start handshaking as soon as the hot-swapping is done.
USB Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad ...
ports and FireWire ports are plug-and-play. Auto-detect or auto-detection ports are usually plug-and-play, but they offer another type of convenience. An auto-detect port may automatically determine what kind of device has been attached, but it also determines what purpose the port itself should have. For example, some
sound card A sound card (also known as an audio card) is an internal expansion card that provides input and output of audio signals to and from a computer under the control of computer programs. The term ''sound card'' is also applied to external audio i ...
s allow plugging in several different types of audio speakers; then a dialogue box pops up on the computer screen asking whether the speaker is left, right, front, or rear for
surround sound Surround sound is a technique for enriching the fidelity and depth of sound reproduction by using multiple audio channels from speakers that surround the listener ( surround channels). Its first application was in movie theaters. Prior to sur ...
installations. The user's response determines the purpose of the port, which is physically a 1/8" tip-ring-sleeve mini jack. Some auto-detect ports can even switch between input and output based on context. As of 2006, manufacturers have nearly standardized colors associated with ports on personal computers, although there are no guarantees. The following is a short list: * Orange, purple, or grey: Keyboard PS/2 * Green: Mouse PS/2 * Blue or magenta: Parallel printer DB-25 * Amber: Serial DB-25 or DB-9 * Pastel pink: Microphone 1/8" stereo (TRS) minijack * Pastel green: Speaker 1/8" stereo (TRS) minijack
FireWire IEEE 1394 is an interface standard for a serial bus for high-speed communications and isochronous real-time data transfer. It was developed in the late 1980s and early 1990s by Apple in cooperation with a number of companies, primarily Sony an ...
ports used with video equipment (among other devices) can be either 4-pin or 6-pin. The two extra conductors in the 6-pin connection carry electrical power. This is why a self-powered device such as a camcorder often connects with a cable that is 4-pins on the camera side and 6-pins on the computer side, the two power conductors simply being ignored. This is also why laptop computers usually have only 4-pin FireWire ports, as they cannot provide enough power to meet requirements for devices needing the power provided by 6-pin connections. Optical (light) fiber, microwave, and other technologies (i.e., quantum) have different kinds of connections, as metal wires are not effective for signal transfers with these technologies. Optical connections are usually a polished glass or plastic interface, possibly with an oil that lessens refraction between the two interface surfaces. Microwaves are conducted through a pipe, which can be seen on a large scale by examining microwave towers with "funnels" on them leading to pipes. Hardware
port trunking In computer networking, link aggregation is the combining ( aggregating) of multiple network connections in parallel by any of several methods, in order to increase throughput beyond what a single connection could sustain, to provide redundan ...
(HPT) is a technology that allows multiple hardware ports to be combined into a single group, effectively creating a single connection with a higher
Bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...
sometimes referred to as a double-barrel approach. This technology also provides a higher degree of
fault tolerance Fault tolerance is the property that enables a system to continue operating properly in the event of the failure of one or more faults within some of its components. If its operating quality decreases at all, the decrease is proportional to the ...
because a failure on one port may just mean a slow-down rather than a dropout. By contrast, in software port trunking (SPT), two agents (websites, channels, etc.) are bonded into one with the same effectiveness; i.e.,
ISDN Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Wo ...
B1 (64K) plus B2 (64K) equals data throughput of 128K.


Types of ports


Digital Visual Interface

Digital Visual Interface Digital Visual Interface (DVI) is a video display interface developed by the Digital Display Working Group (DDWG). The digital interface is used to connect a video source, such as a video display controller, to a display device, such as a co ...
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DVI Digital Visual Interface (DVI) is a video display interface developed by the Digital Display Working Group (DDWG). The digital interface is used to connect a video source, such as a video display controller, to a display device, such as a comp ...


DisplayPort

DisplayPort DisplayPort (DP) is a digital display interface developed by a consortium of PC and chip manufacturers and standardized by the Video Electronics Standards Association (VESA). It is primarily used to connect a video source to a display device su ...
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eSATA

ESata SATA (Serial AT Attachment) is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the earlier Parallel ATA (PATA) standard t ...
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PS/2

PS/2 connector The PS/2 port is a 6-pin mini-DIN connector The mini-DIN connectors are a family of multi-pin electrical connectors used in a variety of applications. Mini-DIN is similar to the larger, older DIN connector. Design Mini-DIN connectors ...
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Mini-DIN connector The mini-DIN connectors are a family of multi-pin electrical connectors used in a variety of applications. Mini-DIN is similar to the larger, older DIN connector. Design Mini-DIN connectors are in diameter and come in seven patterns, wi ...


Serial

Serial port In computing, a serial port is a serial communication interface through which information transfers in or out sequentially one bit at a time. This is in contrast to a parallel port, which communicates multiple bits simultaneously in parallel. ...
" widths="200px" heights="120px" perrow="3"> File:Serial port.jpg File:CAN Connecteur.svg,
DE-9 The D-subminiature or D-sub is a common type of electrical connector. They are named for their characteristic D-shaped metal shield. When they were introduced, D-subs were among the smallest connectors used on computer systems. Description, n ...
VGA connector The Video Graphics Array (VGA) connector is a standard connector used for computer video output. Originating with the 1987 IBM PS/2 and its VGA graphics system, the 15-pin connector went on to become ubiquitous on PCs, as well as many monitors ...
" widths="200px" heights="160px" perrow="3"> File:VGA port.jpg, File:Vga-cable.jpg, File:DE-15 female.svg, D-sub 15


SCSI

SCSI Small Computer System Interface (SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, electrical, optical and logical interface ...
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USB

USB Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad ...
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See also

*
Audio and video connector Audio connectors and video connectors are electrical or optical connectors for carrying audio or video signals. Audio interfaces or video interfaces define physical parameters and interpretation of signals. For digital audio and digital vide ...

infographic - what PC Ports?


References


External links


TVicHW32
Direct Port I/O from Win32
Interface Ports I/O form PC
{{Basic computer components Out-of-band management