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
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.
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:
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
- 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 |