The MS/TP bus is a local or remote network that connects network engines and equipment controllers using the BACnet MS/TP protocol. Two tiers of MS/TP buses exist in the Metasys system architecture. The Field Controller (FC) bus consists of BACnet controllers and point interfaces supervised by a network engine. The Sensor Actuator (SA) bus consists of point interfaces and networked sensors supervised by an equipment controller. To communicate with equipment controllers on a remote MS/TP bus, you need a BACnet/IP to BACnet MS/TP router connected to the building's IP network. For details, refer to the MS/TP Communications Bus Technical Bulletin (LIT-12011034).