They communicate using data Busses using the Chipsets which are the North and South Bridge; the faster components such as the CPU, RAM and Accelerated Graphics Port are controlled by the Northbridge and it communicates to the CPU via the front side buss, the RAM via the Memory Buss and the Accelerated Graphics Port via the Graphics Buss.
http://en.wikipedia.org/wiki/Northbridge_%28computing%29
The Southbridge communicates to the Hard Disk via the ATA Buss, the USB, PCI and BIOS via the LPC Busses; you may find this opinion differs. the S-bridge may communicate to the PCI via the PCI Buss and the USB via the USB Buss.
http://en.wikipedia.org/wiki/Southbridge_%28computing%29
http://en.wikipedia.org/wiki/File:Schema_chipsatz.png
HOPE THIS HELPS :-)
BUS
These are located in the system unit or processing unit.
The basic component inside the system unit is the Central Processing Unit.
Data bus . Shortened from the Latin word Omnibus (for all)
The freeway of parallel connections that facilitates communication between components within and connected to the system unit is known as the system bus. It consists of multiple parallel data lines that transmit data, address, and control signals between the CPU, memory, and peripheral devices. This architecture enables efficient data transfer and coordination among the various components of a computer system.
System Unit
BUSEach channel, called a bus, allows the various devices both inside and attached to the system unit to communicate with each other
BUSEach channel, called a bus, allows the various devices both inside and attached to the system unit to communicate with each other
processor
The components that process data are located in the system unit
Bus
System unit