The purpose of these interface modules is to simply act as a bridge between the control level and field level. Data needs to be transferred between these two levels, and interface modules provide a simple way to do that. In reality, interface modules can be thought of as standard terminal blocks with integrated high-density connectors because they do the exact same thing. However, rather than having discrete connections on both sides, interface modules provide a pluggable connection to the control device. Interface modules can be used by necessity or by convenience: when connecting to a controller with a high-density header, for example a D-Sub header, an interface module will be used out of necessity. In order to transmit a signal from the controller, the user will have to use a D-Sub cable and module to get the signal to the field. However, users can integrate interface modules to attain convenience as well. Interface modules can be utilized instead of terminal blocks when connecting to a PLC. Doing so removes the large number of discrete connections between the controller and the field. Consequently, installations are made faster, wiring errors are eliminated, and there is significant amount of space saved on the DIN rail.