:: Your Computer Technical Resource Headquarters! :: Your Computer Technical Resource Headquarters!
Home arrow Resources & Tools arrow Quick References arrow Computer Ports / Connectors
Thursday, 20 January 2022
Main Menu
Online Store
Web Directory
Featured Sites

Help Support Us!
Support in making a small donation:


Computer Ports / Connectors

Basic Troubleshooting Steps Beep Codes
Computer Ports / Connectors  New Computer Security Threats  New
CPU Types and Specifications DVD Formats  New
File Extensions File Size Conversion Table
HTTP Status Messages IBM Diagnostic Codes
Linux Reference Guide  New Maximum Dedicated Bandwidths
Memory Styles and Types Modem AT Commands, S Registers and RS-232C pins
OSI Network Model Partition Size vs. Cluster Size
RAID Levels Explained  New Regular Expressions  New
Shortcut Keys Standard DMA, I/O and IRQ Assignments
TCP and UDP Port Numbers Technology Reference Cards
Windows XP TCP/IP Utilities - Netsh  New Wireless Networking Standards

PS/2 Ports DB25 Parallel Port USB Port VGA Monitor Port RJ45 Ethernet Port Computer Ports

PS/2 Ports

The PS/2 Ports are simple, 6-pin, low-speed serial connections commonly dedicated to a keyboard and mouse. Although these ports may look identical at first glance, they are not interchangable, so you'll need to be extremely careful to attach the keyboard and mouse to their respective PS/2 port. If you elect to use a USB keyboard and mouse, you can typically disable the PS/2 ports in the system's CMOS setup and free the PS/2 system resources for other devices.

VGA Monitor Port

Video Graphics Array is the display standard for the PC. VGA uses an analog monitor, and PC display adapters output analog signals. All CRTs and most flat panel monitors accept VGA signals, although flat panels may also have a DVI interface for display adapters that output digital signals.

Although VGA may refer to the PC's display system in general, "VGA resolution" typically refers to the original resolution of 640x480 pixels and 16 colors. This base resolution is not widely used except for tiny monitors or booting up the computer in Safe Mode.

DB25 Parallel Port

This interface is found on the back of a PC and is used for connecting external devices such as printers or a scanners. It uses a 25-pin connector (DB-25) and is rather large compared to most new interfaces. The parallel port is sometimes called a Centronics interface, since Centronics was the company that designed the original parallel port standard. It is sometimes also referred to as a printer port because the printer is the device most commonly attached to the parallel port.

RJ45 Ethernet Port

(Registered Jack - Type 45) is a physical interface often used for terminating twisted pair type cables used to connect computers onto a local-area networks (LAN), especially Ethernet. RJ-45 connectors look similar to the RJ-11 connectors used for connecting telephone equipment, but they are a bit wider.


The two most common types are straight-through and crossed-over CAT-5 cables.

Straight-Through: Typically used to connect a computer to a hub, switch or router

Copyright Cisco - Used under Cisco's Terms and Conditions

Crossed-Over: Typically used to connect two hubs, switches or router together. It can also be used to connect two computers directly together.

Copyright Cisco - Used under Cisco's Terms and Conditions

S-Video Port

S-Video connections are available on certain source components and video display devices, and offer a higher level of video performance over composite video signals. By allowing a separate "path" for chroma and luminance (color and brightness) signals, certain video anomalies are alleviated. Generally it is advantageous to use S-video inputs and outputs whenever possible.

Computer monitors, on the other hand, are designed for RGB signals. Most digital video devices, such as digital cameras and game machines, produce video in RGB format. The images look best, therefore, when output on a computer monitor. When output on a television, however, they look better in S-Video format than in composite format.

To use S-Video, the device sending the signals must support S-Video output and the device receiving the signals must have an S-Video input jack. Then you need a special S-Video cable to connect the two devices.

DVI Monitor Port

DVI stands for Digital Visual Interface, and is a new signal input that many newer LCD monitors now offer. DVI offers a completely digital connection from your computer's graphics card to the monitor, and often results in an improved image display with more accurate color representation and sharper overall image quality. Note that many monitors do not currently support DVI, and only the the latest graphics cards offer a DVI output.


There are two variables in every DVI connector, and each represents one characteristic.

The flat pin on one side denotes whether the cable is digital or analog:
  • A flat pin with four surrounding pins is either DVI-I or DVI-A
  • A flat pin alone denotes DVI-D
The pinsets vary depending on whether the cable is single-link, dual-link, or analog:
  • Two separated 9-pin sets (rows of 6) for a single-link cable
  • A solid 24-pin set (rows of 8) for a dual-link cable
  • A separated 8-pin and 4-pin set is for DVI-A

DVI-D Single Link DVI-A DVI-I Single Link
Digital Only Analog Only Digital & Analog
Two sets of nine pins, and a solitary flat blade One set of eight pins and one set of four pins, with four contacts around the blade Two sets of nine pins and four contacts around the blade
DVI-D Dual Link DVI-I Dual Link
Digital OnlyDigital & Analog
Three rows of eight pins and a solitary flat blade Three rows of eight pins and four contacts around the blade

USB Port

Universal Serial Bus: a protocol for transferring data to and from digital devices. Many digital cameras and memory card readers connect to the USB port on a computer. USB card readers are typically faster than cameras or readers that connect to the serial port, but slower than those that connect via FireWire. It is an external bus standard that supports data transfer rates of 12 Mbps. A single USB port can be used to connect up to 127 peripheral devices, such as mice, modems, and keyboards. USB also supports Plug-and-Play installation and hot plugging.

Firewire IEEE 1394 Port

A type of cabling technology for transferring data to and from digital devices at high speed. Some professional digital cameras and memory card readers connect to the computer over FireWire. FireWire card readers are typically faster than those that connect via USB. Also known as IEEE 1394, FireWire was invented by Apple Computer but is now commonly used with Windows-based PCs as well.

Modem RJ-11 Jack

Short for Registered Jack-11, a four- or six-wire connector used primarily to connect telephone equipment. RJ-11 connectors are also used to connect some types of local-area networks (LANs), although RJ-45 connectors are more common.

Mini Audio Jack

Audio connectors are used to affix cables to other audio equipment, providing electronic signal transference and grounding protection. Connectors may be plugs, jacks, or combinations, and may have an integral switch. Plug type audio connectors are a plug, or male, connector includes pins that can be inserted into a socket. Jack type audio connectors are a jack, or female, connector consists of sockets that are aligned to mesh with a pin-type connector. Combination plug and jack connectors are also available. They may also have switches. Includes adapters and Y-adapters. Applications for audio connectors can be general purpose, telephone, or microphone. Most audio connectors are for commercial purposes, but some may conform to military specifications.

Port Color Codes

The most lasting impact of PC 99 was that it set out the color code for the various standard types of plugs and connectors used on PCs. As many of the connectors look very similar, particularly to a novice PC user, this made it far easier for people to connect peripherals to the correct ports on a PC. This color code was gradually adopted by almost all PC, motherboard and peripheral manufacturers.

Color Function Connector
Mouse and Keyboard
  Green PS/2 Mouse / pointing device 6pin miniDIN
  Purple PS/2 Keyboard 6pin miniDIN
I/O Ports
  Black USB port USB Type A
  Grey Firewire / IEEE 1394 6-Pin FireWire 400
  Burgundy Parallel port 25 pin D
  Teal or turquoise Serial port 9 pin D
Video Card
  Blue Analog VGA 15 pin VGA
  White Digital monitor DVI
  Yellow S-Video 6pin miniDIN
  Yellow Composite video RCA jack
Sound Card
  Pink Analog andio input 3.5mm jack
  Light blue Analog line level audio input 3.5mm jack
  Lime green Analog line level audio output for the main stereo signal (front speakers or headphones) 3.5mm jack
  Black * Analog line level audio output for rear speakers 3.5mm jack
  Brown Analog line level audio output for 'Right-to-left speaker' 3.5mm jack
  Orange S/PDIF digital audio output (sometimes used as an analog line output for a center speaker instead) 3.5mm jack
  Gold Game port / MIDI 15 pin D

* Does not appear in the PC 99 specification but are widely used on modern PCs. tries to supply accurate and up-to-date information but it is possible that this page may contain typographical errors or technical inaccuracies. Any errors will be periodically corrected as they are made known to us. If any such errors are found, we would appreciate if you would report them here.
Thank You.

Add New Search
Write comment
[b] [i] [u] [url] [quote] [code] [img] 
Please input the anti-spam code that you can read in the image.

3.22 Copyright (C) 2007 Alain Georgette / Copyright (C) 2006 Frantisek Hliva. All rights reserved."

This site is NOT responsible for any damage that the information on this site may cause to your system. Everything you try, whether inspired by the response given from this site or not, is entirely at your own risk. All product names and company names used herein are for identification purpose only and may be trademarks or registered trademarks of their respective owners. We are in no way affiliated or representing any of the companies on this site unless specified.
Back to Top Back to Top
Generated in 0.28585 Seconds