No. The various devices must cooperate somehow so their data and signals don't get mixed.
The way in which devices connected to a bus cooperate is another part of a bus standard.
Input/output controllers receive input and output requests from the central processor, and then send device-specific control signals to the device they control. They also manage the data flow to and from the device. This frees the central processor from involvement with the details of controlling each device. I/O controllers are needed only for those I/O devices that are part of the system.
Often the I/O controllers are part of the electronics on the main circuit board (the mother board) of the computer. Sometimes an uncommon device requires its own controller which must be plugged into a connector (an expansion slot) on the mother board.
I/O controllers are sometimes called device controllers. The software that directly interacts with a device controller is called a device driver. When you install a new device on your computer (say, a new graphics board) you must also install a device driver for it.
(Review:) Is there a difference between the memory used to hold programs and the memory used to hold data?