Computer Architecture
Ports
Ports
There are lots of external devices that you can connect to your computer. All external devices connect to the computer’s system unit via cables and ports
A port is the slot into which you plug a cable that connects a peripheral to the computer.
Several external devices are attached to your computer already, including a mouse, keyboard, monitor, microphone, and speakers
Computer system and attached external devices
Examples of ports
Whatever external devices you have, they're all connected to the system unit via cables.
Each cable plugs into a specific port on the system unit.
The ports are usually on the back of the system unit. But they can be on front or side as well.
Examples of ports
More about ports
There are two traditional ports in use in all new PCs namely the COM port and the LPT port
COM Ports
Serial port most frequently used to connect a mouse or an external modem to your computer
Serial port used is usually RS 232C port
LPT Ports
A parallel port which is most frequently used to connect the PC to a printer
PS/2 Port
Most computers are equipped with a PS/2 port for connecting a mouse
The reason for the introduction of this port was that it freed up the serial port for other devices.
Universal Serial Bus (USB) Port
Serial port allowing up to 127 devices to be daisy chained to one port
Preferred method of connecting peripherals Speed of 12 MBps USB devices: screens, keyboards, mouse,
modems, printers, hard drives, flash drives, CD Writers, scanners, digital cameras, GPS, web cams
Built into most motherboards
USB 2.0
Improves USB speed and reliability further
Transfers data at 480 MBps Backward compatible with USB1 Compete with Firewire devices Improves speed of CD writers, hard
drives, digital still and video cameras
Plug and Play
Detects and configures a new device automatically without requiring a manual installation.
The computer must be rebooted before the operating system will detect the device.
Hot swappable/Hot plugging
An extension of plug and play Devices can be plugged in and out
while the computer is running and without having to reboot the computer
Devices can be added and removed while a computer is running
http://www.howstuffworks.com/usb.htm
http://computer.howstuffworks.com/firewire.htm
USB Hubs
A hub typically has four new ports, but may have many more. You plug the hub into your computer, and then plug your devices (or other hubs) into the hub. By chaining hubs together, you can build up dozens of available USB ports on a single computer.
USB and Firewire ports/logos
Firewire Serial communications standard Can connect up to 63 devices via a hub IEEE 1394 specification Allows transfer of data at high speeds up to
400 MBps. Latest version 800 MBps Becoming a standard on new PCs Features on most digital video cameras for
transfer of digital video for editing Other devices: external hard drives, CD writers
Wireless connection
Most common is called BLUETOOTH Wireless networking connection based on
very high frequency radio signals with a short range (10 – 15 meters)
Allows various electronic devices to talk to each other without physical connection
Without user intervention Through walls
Firewire
Edit & create custom video projects using fast hard drives, a digital camcorder and a computer.
Download video automatically with perfect digital clarity.
Content digital from start to finish – no loss of quality
AGP ( Advanced Graphic Port)
Faster video performance Single slot on a Pentium II, III and IV
motherboard for use with AGP graphic cards only AGP graphics cards can transfer data +_8 times
faster than a graphics card plugged into a PCI slot
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