Aim:
To identify the front panel indicators and switches in a computer system
Procedure:
:
Hard Drive Activity LED
Connecting pins 1 and
3 to a front panel mounted LED provides visual indication that data is being read
from or written to the hard drive.
Reset Switch
Supporting the reset
function requires connecting pins 5 and 7 to a momentary-contact switch that is
normally open. When the switch is closed, the board resets and runs POST.
Power Switch
Supporting the power
on/off function requires connecting pins 6 and 8 to a momentary-contact switch
that is normally open. The switch should maintain contact for at least 50 ms to
signal the power supply to switch on or off.
Drive bays
Drive bays are most
commonly used to store disk drives, although they can also be used for
front-end USB ports, I/O bays, card readers, fans, tool storage, and other
uses.
· 5.25" - Full-height bays
were found in old PCs in the early to mid-1980s. They were approximately
3.5" high by 5.75" wide, and used mainly for hard disks and floppy
disk drives. Half-height drive bays are approximately 1.75" high by
5.75" wide, and are the standard housing for CD and DVD drives in modern
computers, but were sometimes used for other things, including hard disks and
floppy disk drives in the past.
· 3.5" - 3.5" bays, like
their larger counterparts, are named after diskette dimensions; their actual
dimensions are 4" wide by 1" high. Those with an opening in the front
of the case are generally used for floppy or Zip drives
Ffront Side Connectors:
USB Connectors
· USB
(Universal Serial Bus) is a way of setting up communication between a computer
and peripheral devices. USB is intended to replace many varieties of serial and
parallel ports. USB can connect computer peripherals such as mice, keyboards,
PDAs, gamepads and joysticks, scanners, digital cameras, printers, personal
media players, flash drives, and external hard drives.
Card Reader:
· Card
reader" is the generic term for an input device that reads flash memory
cards. It can be a standalone device that connects to a computer via USB or it
may be integrated into a computer, printer, or multifunction device. In fact,
most multifunction printer/scanner/copiers now have built-in card readers.
· Most
card readers accept multiple memory card formats, including compact flash (CF),
secure digital (SD), and Sony's Memory Stick. Some card readers accept various
other formats such as XD, SmartMedia, Microdrive, and Memory Stick Pro Duo
cards.
Audio Jack:
· A
socket for plugging in an audio source, Audio jacks are found on many types of
audio equipment and musical instruments that accept external sound sources. In
a car or truck, an audio jack, also called a "media jack" or
"auxiliary (AUX) jack," is a mini-phone socket that connects any
portable music player to the vehicle's amplifier and speakers.
Rear Side Connectors:
PS/2 Port:
· The
PS/2 standard, introduced by IBM in 1987, stands for Personal System/2.
A PS/2 port is an electronic receptacle or plug found on computers. It accepts
a PS/2 cable with a mini-DIN connector, and is most often used to plug in a
keyboard or mouse.
· The
PS/2 port is female while the mini-DIN cable is male. The connector is small
with a diameter of about 1/3 inch (9.5mm). It features a metal sleeve that is notched
to ensure proper alignment when inserting it into the PS/2 port. This protects
the circular pins inside the DIN connector from becoming bent.
USB Port:
· A
USB port is a standard cable connection interface on personal computers and
consumer electronics. USB ports allow stand-alone electronic devices to be
connected via cables to a computer (or to each other).
· USB
stands for Universal Serial Bus, an industry standard for short-distance digital
data communications. USB allows data to be transferred between devices. USB
ports can also supply electric power across the cable to devices without their
own power source.
· Both
wired and wireless versions of the USB standard exist, although only the wired
version involves USB ports and cables.
Parallel Port:
· This
interface is found on the back of older PCs and is used for connecting external
devices such as printers or a scanner. 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. The latest parallel port standard, which supports the same
connectors as the Centronics interface, is called the Enhanced Parallel Port
(EPP). This standard supports bi-directional communication and can transfer
data up to ten times faster than the original Centronics port. However, since
the parallel port is a rather dated technology, don't be surprised to see USB
or Firewire interfaces completely replace parallel ports in the future.
Serial Port:
· The
serial port is a type of connection on PCs that is used for peripherals such as
mice, gaming controllers, modems, and older printers. It is sometimes called a
COM port or an RS-232 port, which is its technical name. If that's not enough
to confuse you, there are two types of serial ports -- DB9 and DB25. DB9 is a
9-pin connection, and DB25 is, you guessed it, a 25-pin connection.
· A
serial port can only transmit one bit of data at a time, whereas a parallel
port can transmit many bits at once. The serial port is typically the slowest
port you'll find on a PC, if you find one at all. Most new computers have
replaced serial ports with much faster and more compatible USB ports.
Result:
Thus the switches, indicators and the connectors of the pc’s are identified
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