control bus
The control bus is part of the system bus of a computer.
The control bus is connected to the processor's control unit, the memory and the input/output units and transmits the signals bidirectionally that are required for controlling the data transfer.
This includes the bus request, interrupts, handshaking, etc. The control bus has lines to indicate the direction of transfer, via this it is indicated whether it is a matter of reading out or reading in data, furthermore there are lines to distinguish the memory and the input/output units.