The S700 I/O family is a highly flexible and modular process I/O system that communicates with parent controllers and PLCs over industry-standard Fieldbus technology, permitting a virtually infinite number of installation and communication arrangements for any application. Module Termination Units (MTUs) host S700 I/O modules and are keyed to ensure the correct module is used. Many Module Termination Units (MTUs) options are available for various S700 I/O modules to meet your project requirements.