Computer Ports / Connectors

 

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.


 TYPES OF RJ-45 CABLES 

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

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

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.

HOW TO RECOGNIZE A DVI CABLE

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

 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