An interface controller is a device or module that controls and configures the interface of a processor system to a network or other interconnection. There are many different types of interfaces in electronic systems. Controllers typically configure, maintain current status, handle faults, and provide the implementation of the algorithm to transfer data successfully to and from the Interface. This may also include generating interrupt events to signal the processor when things relating to the interface have occurred.

An example of an interface controller is a network interface controller (NIC).

A NIC is a peripheral card that plugs into a computer and provides an Ethernet interface. The NIC controls the access of the computer to the Ethernet, but can also have versions that control access to fiber channels, token rings or even WiFi. In the case of a NIC, it is not just controlling the physical layer, but it is also controlling the data link layer, which extends control to being embedded in the data packets themselves.

Other interface controllers are available that perform similar roles to the Ethernet controller in a NIC. These include CAN bus controllers, and USB hub controllers. Pick an interface, and there is a controller that manages it.  A more generic example is an embedded microcontroller. A PIC microcontroller is a typical example of a large number of embedded microcontrollers available today. PIC stands for peripheral interface controller, so named because it has a rich I/O space of peripheral functionality.  It enables a programmer to implement simple software algorithms to manage the control I/O, serial communications, sensors and actuators available in embedded systems. This could include driving LED, or LCD displays through serial port connect to special purpose devices and detecting key presses.  In this case, the interface being describes could be the user interface, and could also be the control interfaces.