Computer port (hardware)

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Examples of computer connector sockets on various laptops Computer-connector-sockets.jpg
Examples of computer connector sockets on various laptops
Ports on the back of the Apple Mac Mini (2005) Mac-mini-dvi-back.jpg
Ports on the back of the Apple Mac Mini (2005)

A computer port is a hardware piece on a computer where an electrical connector can be plugged to link the device to external devices, such as another computer, a peripheral device or network equipment. [1] This is a non-standard term.

Contents

Electronically, the several conductors where the port and cable contacts connect, provide a method to transfer data 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 female 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, etc.), square (Telephone plug), trapezoidal (D-Sub — the old printer port was a DB-25), etc. There is some standardization to physical properties and function. For instance, most computers have a keyboard port (currently a Universal Serial Bus USB-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 could have been used for monochrome video, color analog video (in two incompatible standards), a joystick interface, or a MIDI 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 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:

After ports are connected, they typically require handshaking, 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 ports are designed so that the connected devices automatically start handshaking as soon as the hot-swapping is done. USB 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 cards 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 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:

Additionally, USB ports are color-coded according to the specification and data transfer speed, e.g. USB 1.x and 2.x ports are usually white or black, and USB 3.0 ones are blue. SuperSpeed+ connectors are teal in color. [2]

FireWire 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 (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 sometimes referred to as a double-barrel approach. This technology also provides a higher degree of fault tolerance 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 B1 (64K) plus B2 (64K) equals data throughput of 128K.

The USB-C standard, published in 2014, supersedes previous connectors and is reversible (although not electrically), meaning it can be plugged both ways. Reversible plugs have a symmetric pinout. Other reversible connectors include Apple's Lightning. [3] [4] [5]

Types of ports

Digital Visual Interface

DisplayPort

eSATA

PS/2

Serial

SCSI

USB

See also

Related Research Articles

<span class="mw-page-title-main">RS-232</span> Standard for serial communication

In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a DTE such as a computer terminal or PC, and a DCE, such as a modem. The standard defines the electrical characteristics and timing of signals, the meaning of signals, and the physical size and pinout of connectors. The current version of the standard is TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange, issued in 1997. The RS-232 standard had been commonly used in computer serial ports and is still widely used in industrial communication devices.

<span class="mw-page-title-main">USB</span> Standard for computer data connections

Universal Serial Bus (USB) is an industry standard that allows data exchange and delivery of power between many types of electronics. It specifies its architecture, in particular its physical interface, and communication protocols for data transfer and power delivery to and from hosts, such as personal computers, to and from peripheral devices, e.g. displays, keyboards, and mass storage devices, and to and from intermediate hubs, which multiply the number of a host's ports.

<span class="mw-page-title-main">Serial port</span> Communication interface transmitting information sequentially

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. Throughout most of the history of personal computers, data has been transferred through serial ports to devices such as modems, terminals, various peripherals, and directly between computers.

<span class="mw-page-title-main">Parallel port</span> Computer interface

In computing, a parallel port is a type of interface found on early computers for connecting peripherals. The name refers to the way the data is sent; parallel ports send multiple bits of data at once, as opposed to serial communication, in which bits are sent one at a time. To do this, parallel ports require multiple data lines in their cables and port connectors and tend to be larger than contemporary serial ports, which only require one data line.

<span class="mw-page-title-main">Apple Desktop Bus</span> Proprietary bit-serial peripheral bus

Apple Desktop Bus (ADB) is a proprietary bit-serial peripheral bus connecting low-speed devices to computers. It was introduced on the Apple IIGS in 1986 as a way to support low-cost devices like keyboards and mice, enabling them to be connected together in a daisy chain without the need for hubs or other devices. Apple Desktop Bus was quickly introduced on later Macintosh models, on later models of NeXT computers, and saw some other third-party use as well. Like the similar PS/2 connector used in many PC-compatibles at the time, Apple Desktop Bus was rapidly replaced by USB as that system became popular in the late 1990s; the last external Apple Desktop Bus port on an Apple product was in 1999, though it remained as an internal-only bus on some Mac models into the 2000s.

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 resource conflicts. The term "plug and play" has since been expanded to a wide variety of applications to which the same lack of user setup applies.

<span class="mw-page-title-main">SATA</span> Computer bus interface for storage devices

SATA 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 to become the predominant interface for storage devices.

<span class="mw-page-title-main">Serial communication</span> Type of data transfer

In telecommunication and data transmission, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels.

GeoPort is a serial data system used on some models of the Apple Macintosh that could be externally clocked to run at a 2 megabit per second data rate. GeoPort slightly modified the existing Mac serial port pins to allow the computer's internal DSP hardware or software to send data that, when passed to a digital-to-analog converter, emulated various devices such as modems and fax machines. GeoPort could be found on late-model 68K-based machines as well as many pre-USB Power Macintosh models and PiPPiN. Some later Macintosh models also included an internal GeoPort via an internal connector on the Communications Slot. Apple GeoPort technology is now obsolete, and modem support is typically offered through USB.

<span class="mw-page-title-main">IBM PS/2</span> Second generation of personal computers by IBM

The Personal System/2 or PS/2 is IBM's second generation of personal computers. Released in 1987, it officially replaced the IBM PC, XT, AT, and PC Convertible in IBM's lineup. Many of the PS/2's innovations, such as the 16550 UART, 1440 KB 3.5-inch floppy disk format, 72-pin SIMMs, the PS/2 port, and the VGA video standard, went on to become standards in the broader PC market.

<span class="mw-page-title-main">Mattel Aquarius</span> 1983 home computer

Aquarius is a home computer designed by Radofin and released by Mattel Electronics in 1983. Based on the Zilog Z80 microprocessor, the system has a rubber chiclet keyboard, 4K of RAM, and a subset of Microsoft BASIC in ROM. It connects to a television set for audiovisual output, and uses a cassette tape recorder for secondary data storage. A limited number of peripherals, such as a 40-column thermal printer, a 4-color printer/plotter, and a 300 baud modem, were released. The Aquarius was discontinued in October 1983, only a few months after it was launched.

<span class="mw-page-title-main">D-subminiature</span> Type of electrical connector

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.

<span class="mw-page-title-main">VGA connector</span> 15-pin video 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, projectors and HD television sets.

<span class="mw-page-title-main">IEEE 1284</span> Standard for parallel peripheral interfaces, known as the Centronics port

IEEE 1284, also known as the Centronics port, is a standard that defines bi-directional parallel communications between computers and other devices. It was originally developed in the 1970s by Centronics before its IEEE standardization.

<span class="mw-page-title-main">USB On-The-Go</span> Specification for USB devices

USB On-The-Go is a specification first used in late 2001 that allows USB devices, such as tablets or smartphones, to also act as a host, allowing other USB devices, such as USB flash drives, digital cameras, mouse or keyboards, to be attached to them. Use of USB OTG allows devices to switch back and forth between the roles of host and device. For example, a smartphone may read from removable media as the host device, but present itself as a USB Mass Storage Device when connected to a host computer.

The mini-DIN connectors are a family of multi-pin electrical connectors used in a variety of applications. Mini-DIN 9.5 millimetres is similar to the larger, older 13.2 mm diameter DIN connector.

<span class="mw-page-title-main">PS/2 port</span> 6-pin mini-DIN connector for connecting keyboards and mice to a PC compatible computer

The PS/2 port is a 6-pin mini-DIN connector used for connecting keyboards and mice to a PC compatible computer system. Its name comes from the IBM Personal System/2 series of personal computers, with which it was introduced in 1987. The PS/2 mouse connector generally replaced the older DE-9 RS-232 "serial mouse" connector, while the PS/2 keyboard connector replaced the larger 5-pin/180° DIN connector used in the IBM PC/AT design. The PS/2 keyboard port is electrically and logically identical to the IBM AT keyboard port, differing only in the type of electrical connector used. The PS/2 platform introduced a second port with the same design as the keyboard port for use to connect a mouse; thus the PS/2-style keyboard and mouse interfaces are electrically similar and employ the same communication protocol. However, unlike the otherwise similar Apple Desktop Bus connector used by Apple, a given system's keyboard and mouse port may not be interchangeable since the two devices use different sets of commands and the device drivers generally are hard-coded to communicate with each device at the address of the port that is conventionally assigned to that device.

A SCSI connector is used to connect computer parts that communicate with each other via the SCSI standard. Generally, two connectors, designated male and female, plug together to form a connection which allows two components, such as a computer and a disk drive, to communicate with each other. SCSI connectors can be electrical connectors or optical connectors. There have been a large variety of SCSI connectors in use at one time or another in the computer industry. Twenty-five years of evolution and three major revisions of the standards resulted in requirements for Parallel SCSI connectors that could handle an 8, 16 or 32 bit wide bus running at 5, 10 or 20 megatransfer/s, with conventional or differential signaling. Serial SCSI added another three transport types, each with one or more connector types. Manufacturers have frequently chosen connectors based on factors of size, cost, or convenience at the expense of compatibility.

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 video, this can be thought of as defining the physical layer, data link layer, and most or all of the application layer. For analog audio and analog video these functions are all represented in a single signal specification like NTSC or the direct speaker-driving signal of analog audio.

The initial versions of the USB standard specified connectors that were easy to use and that would have acceptable life spans; revisions of the standard added smaller connectors useful for compact portable devices. Higher-speed development of the USB standard gave rise to another family of connectors to permit additional data paths. All versions of USB specify cable properties; version 3.x cables include additional data paths. The USB standard included power supply to peripheral devices; modern versions of the standard extend the power delivery limits for battery charging and devices requiring up to 240 watts. USB has been selected as the standard charging format for many mobile phones, reducing the proliferation of proprietary chargers.

References

  1. "What is a computer port?". TechTarget. 2024. Retrieved February 18, 2024.
  2. "A Brief Introduction to USB Color Code (USB Wire & Port)". PartitionWizard. July 6, 2023. Retrieved July 12, 2024.
  3. "Definition of reversible plug". PCMag . Retrieved July 12, 2024.
  4. "USB Type-C® Cable and Connector | Language Usage Guidelines from USB-IF" (PDF). USB-IF . Archived from the original on March 9, 2023.{{cite web}}: CS1 maint: unfit URL (link)
  5. Campbell, Mikey (May 9, 2013). "Apple's Lightning connector detailed in extensive new patent filings". Appleinsider . Retrieved July 12, 2024.