The interface of a module is a description of all the externally visible operations and what other modules need to know and do to make use of them, but without any details of how the operations are implemented internally. Network Interface Module (NIM) is a front-end receiver block, which interfaces incoming signals from outside world in to the High Definition (HD) Radio Frequency (RF) receivers. In most of the cases, NIM receives only one type of signal and down converts RF in to Intermediate Frequency (IF).
The interface module is optional or an additional module. It is used for the rack to rack communication in multi-tier configuration in modular PLC system. A module is used to specify the functionality of the logic. For example if you are building a counter you would use a module to define the functionality (up behavior/down behavior/reset behavior) of the counter. An interface as the name suggests is used to specify the interface behaviour.
The Control Interface Module (CIM) is designed to allow for low voltage termination of environmental control and monitoring devices. Interface Functions. Interface functions allow you to link your model to external data sources such as text files, databases, spreadsheets and external applications.