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1. M Adeel

2.  Computer ports are connection points or
interfaces with other peripheral devices. There
are two main type of computer ports:
 Parallel Ports
 Serial Ports
 Others types are also there
 PS2, SCSI etc.

4.  Parallel port is used for data transfer
between a computer and a peripheral
device through a 25 or 36 pin connector.
 In parallel communication multiple bits
are transferred at a time.
 By using the IEEE 1284 standard
the parallel port becomes a bidirectional
data gateway (can be used for
transferring and receiving data packages).

5.  The parallel port speed can range from 50
KBps to 150 KBps and can go up to 2 MBps.
 The 2 MBps speed is achieved when the EPP
and ECP modes are used as a 32 or 16 bit
transfer interface who uses a 8 bit IN / OUT
hardware.

6.  Parallel port pinout description (db25 and
Centronics 36 pin connector) :

7.  Serial port is a electronic communication
gateway used for transferring data one bit at a
time.
 Together with parallel port the serial port was
used almost for all type of information transfer
between a computer and other peripheral
devices.
 Today the serial port has been replaced with
dedicated ports like usb port (used for data
transfer and communication between a
computer and other devices), vga port (video
Graphic Array), Ethernet port or internet port
(used for network communication; any type of
information) .

9.  In our days the serial port is most used on
industrial devices and programming.
 Serial port programming is done by using a serial
port adapter to a usb port mostly because the
new computers are not equipped with db9
connectors.
 The disappearance of the external serial
communication doesn’t mean that this type of
data transfer is not used any more on the new
PC’s because it migrated inside the computer
and you could know it by the name of SATA or
serial ATA.
 SATA is used for data transfer between optical
devices ( dvd drive ) , hard disk drives and the
motherboard.

10.  The PS2 port is used for connecting
keyboards and mice to a PC. This standard
was introduced in 1987 by IBM with main
purpose of replacing the serial keyboard and
mouse.

11.  In our days ps/2 port was replaced by usb port,
which is more easy to implement on a PC even
though ps2 offers more capability and a greater
speed.
 When this standard was released the keyboard and
mouse port had the same color, black like the
connector or white like the connecting cable. Modern
ps2 ports are colored different event thought the
pinout configuration is the same.
 PS2 connector color code
 Purple – Keyboard
 Green – Mouse
 Ps2 Mini-DIN connector has 6 pins and carries a serial
signal at frequencies starting from 10 up to 16 kHz
with one start bit, one stop bit and one parity bit.

12. Pin1 – Data
Pin2 – Not connected
Pin3 – Ground
Pin4 – VDC +5V at 275 mA
Pin5 – Clock
Pin6 – Not connected

13.  USB port ( Universal Serial Bus ) is the most
used connection point for data transfer in
the world.
 It was created in the mid-1990s with the
intention of replacing all other PC ports
like serial port , parallel port , PS/2 port .
 A standard usb connector is a simple socket
with 4 pins : one for power, one for ground
and two for data transfer

14.  In 1996 USB 1 was released. It had
a speed range between 1.5 Mb/s and
12 Mb/s. Four years later USB 2.0
port was released and had a
maximum speed of 480 Mb/s. The usb
2.0 brought with it new devices like
usb flash drive or memory stick , usb
hard drive , usb camera and many
other.
 Recent development in storage
devices increase the need for higher
transfer speeds and in 2008 USB 3.0
was release. This technology can
reach speeds of 5 Gb/s which is 10
times faster than USB 2.0
 A usb port can be connected with
almost all other port type
like Ethernet port or firewire port by
using a usb adapter. The usb adapter
can be a circuit in a box with an usb
port ant one end and a compatible
port at the other or a simple usb
cable.

15.  USB Pinout
 Pin 1 – VCC +5V
 Pin 2 – Data –
 Pin 3 – Data +
 Pin 4 – GND

16.  Firewire port or IEEE 1394 was first
developed in 1990 by Apple and worked as a
serial bus interface for high speed data
transfer. The standard was first introduced
on computers in 2000 and became the main
data connection port for apple
 Firewire IEEE 1394 port supports the
following operating systems: Mac OS 8.6, 9,
Mac OS X, Microsoft Windows, Haiku, Linux,
FreeBSD and NetBSD..

18.  Ethernet port is a network hardware interface
used for data transfer and control between at
least two devices that can support the ip
protocol.
 It was introduced in 1980 and, at first, coaxial
cable was used. In 1985 the Ethernet port was
standardized and twisted pair cable replaced the
coaxial cable.
 Twisted pair cable is used only on short
distances, like the connection between a
computer modem port or network port and a
Ethernet switch or router. On long distances
fiber optic links are used as Ethernet cable.

20.  The Ethernet port speed can vary 10Mbps up
to 10Gbps. High speeds are usually used in
large data transfer networks like a CCTV IP
network or cable company but in the last
case high speed is only obtained between
switches or routers in most cases the client
receives only 10 or 100 Mbps.

21.  The maximum Ethernet cable length
between switches computers and routers is
100 meters or 328ft. After this the signal
starts losing in amplitude and you could
experience connection loss. If you want to
use internet cables on longer distances it is
better to use signal boosters for every 100
meters. A more efficient way is to use fiber
optic cable who with special equipment can
go up to 20 km without any signal booster.

22. DAE CITII