Invensys Triconex 4201 RXM Communication ModuleRemote Extender Module (RXM) RXMs and chassis enable I O modules to be positioned several kilometers away from the main chassis. RXM sets, comprising three identical modules, act as repeaters and extenders of the Tricon I O bus while offering ground loop isolation. A primary RXM set facilitates three remote locations by linking to three remote RXM sets housed in a remote chassis. Triconex 4201 RXM Communication Module RXM Model: 42011 RXM Chassis