Extending The Processor`s Power To Other Devices

• Ports
• Expansion Slots and Boards

Ports: 

• External devices-such as those used for input and output-are connected to the system by ports on the back of the computer.
• PC`s feature a number of built-in ports,which are ready to accept devices such as printer,mouse,keyboard,phone line,microphone and speakers and others
• Most computers come with a serial port and a parallel port.A serial port transmits one bit of data at a time;a parallel port transmits data one byte at a time.

Expansion Slots and Boards: 

• If the PC does not have a port for an external device,we can install an expansion board into one of the empty expansion slots.
• A board provides the correct port for the new device, and connects the device to the CPU by way of the computers expansion bus.
• Newer bus technologies such as Universal Serial Bus(USB)and IEEE 1394 enable many devices to be connected to one port.
• Small computer system Interface(SCSI) is an older standard for extending the bus to multiple devices through a single port.