An interface module can be a module that is used in factory automation and industrial environments to provide a rugged and reliable interface to sensors and actuators for a programmable logic controller (PLC). An interface module usually attaches to a field fus (for example, Profibus) or an industrial Ethernet interface  (like Profinet) and provides for centralized or decentralized peripherals. In many cases, an interface module sits in a rack with a separate power supply and a CPU Module. Actuators and sensor modules (signal modules ) interfaced to by an interface module include relays controllers, solenoid valves, temperature sensors, pumps, motors, motor controllers and lamps.  Control communications are highly resistant to noise to allow the units to operate reliably in noisy factory environments. They are typically hot swappable (in case of failure), have user-friendly wiring connection capability, fault and status LED indicators and sport a solid, environment and vibration resilient chassis.

Interface modules can also be modules specifically designed to link incompatible hardware or expand the capabilities of logic systems. They may include diodes, fuses, optocouplers, level shifters, power supplies or a number of other components to facilitate converting one interface into another. They may also need to adapt the connectors used in one system to those used in another. In some cases, one finds interface modules that are DIN rail mountable or can be panel mounted for specific applications.

There are interface modules that specifically convert between communications bus standards. These usually have connectors compatible with the standards being converted between and an IC that is specifically designed for the conversion. Examples of conversion module types that are commonly available include RS232 to USB, JTAG to USB and SPI to I2C. Such conversion boards are commonly available from hobby electronics shops as bus conversion is a very common problem to have when interconnecting systems.