external data bus
It controls the part of the external data bus connected to the expansion slots.
In computers, the bus is the subsystem that transfers data between internal parts of the computer, or from internal parts of the computer to external parts, or between two computers. External bus can be parallel (ATA (and all of its derivations), IEEE-488, SCSI) or serial (USB, FireWire, etc.).
The external data bus can be as wide as desired, given the necessary compromises between performance, complexity, and cost. The wider the bus, the faster the theoretical aggregate data transfer rate. In the 8085 and 8088, the external data bus is 8 bits wide; in the 8086, it is 16 bits wide; in the 80386, it is 32 bits wide; and in the modern incarnations of 64 bit processors, it is 64 bits wide.
It is my understanding that the 80286 has a 16-bit data bus. This was a doubling of the original 8086/8088 processors.
A data bus connects different parts of a circuit and comprises a group of parallel wires, each one carrying a different logic signal.
The contents of the stack pointer and program counter are loaded into the address buffer and address-data buffer. These buffers are then used to drive the external address bus and address-data bus. As the memory and I/O chips are connected to these buses, the CPU can exchange desired data to the memory and I/O chips. The address-data buffer is not only connected to the external data bus but also to the internal data bus which consists of 8-bits. The address data buffer can both send and receive data from internal data bus.
USB
Which processor has a 32-bit Data Bus and a 24-bit Address Bus?
Internal data bus is defined as a collection or a sequence of the signal line that are responsible for carrying data from one computer to another computer or from one destination to another destination. Basically it is used to transfer data to the external drives and also referred as the internal bus.
Memory Controller Chip
Data bus moves data inside your computer. Normal cable moves data external. Data buses are parallel and most network media is serial. Some media is also analog where as the data bus passes data digitally. There are many differences but to be more specific would depend on which 'normal cable' you are referring too.