The IOM37 input/output expansion module is a part of the Metasys?« system Field Equipment Controller family. Input/Output Module (IOM) expansion modules expand the number of points connected to a Network Automation Engine (NAE), Network Control Engine (NCE), Field Equipment Controller (FEC), VAV Modular Assembly (VMA), or Advanced Application Field Equipment Controller (FAC) to monitor and control a wide variety of HVAC equipment. IOMexpansionmodulesoperateonanRS-485BACnet?« MS/TP Bus and integrate into Johnson Controls?« and third-party BACnet systems.. Johnson Controls. Johnson Controls. MS-IOM3711-0.