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Description

• Printed metal traceses on the motherboard or circuit board called as bus lines.
• CPU communicates with other devices on motherboard like memory, expansion cards, co-processor and keyboards via bus lines.
• Data is in the form of electrical signals either low current zero or high current one.
• Set of parallel buses is like highway for the data, which increases the computer performance.
• Advantages: Simplifies the design of the motherboard, Reduces the circuitry and the cost.

Types of buses

Data bus:

• Is a path that connects the CPU, memory and other devices on the motherboard.
• Data is transferred form one system component to another using these lines.
• More number of bus lines increases the speed of data transfer because each bus line can transfer one bit at a time.
• The number of bit processor determines the value of data bus i.e. 32-bit processor has 32-bit data bus.

Address bus:

• Is same like data bus.
• Connection is between CPU and RAM and carries memory address instead of data.
• Number of address bus lines determines maximum number of memory address.

Bus has four communication standard

ISA (Industry Standard Architecture):

• 8 bit or 16 bit wide.
• Transfer 16 bit at a time with 98 slots black in color.
• It has speed up to 8-40 Mhz.

EISA (Extended ISA):

• ISA cards works on EISA slots and supports plug and play.
• Automatically configures adaptor cards by simply plugging in.
• Transfers 32 bit of data at a time.
• Brown in a color and has 188 slots.

PCI (Peripheral Component Interconnection):

• Can transfer 32 or 64 bit data at a time.
• Speed up to 38-48 MHz with 120 slots.
• White in a color and supports plug and play.

USB ( Universal Serial Bus):

• Speed varies between 12 MBPS to 4.3 GBPS depending on version 1.0, 2.0, 3.0.
• Supports plug and play, hot plugging etc.