Specifications

Document Introduction
The BACnet® protocol Master-Slave/Token-Passing (MS/TP) communications bus is a local network that connects
supervisory controllers and field controllers to field point interfaces.
This document describes the specifications, device limits, and rules of the MS/TP communications bus, as well as
how to wire and terminate devices, and troubleshoot device communication on the MS/TP bus. The remote MS/TP
field bus is also described. With the addition of a BACnet IP to BACnet MS/TP Router, the Remote Field Bus allows
connection to remote field controllers over IP.
This document is intended for the user who needs to know the rules, requirements, limits, specifications, and
configuration of the MS/TP bus to design, wire, or troubleshoot an MS/TP application.
Related Documentation
Table 1 lists the related documentation that describes controllers and systems related to the MS/TP communications
bus.
Table 1: Related Documentation
See DocumentFor Information On
Metasys® System Configuration Guide (LIT-12011832)
Metasys® System Limitations and Overview
NAE55/NIE55 Installation Instructions (Part No. 24-10051-43)
Installation and Specifications of the NAE55
NAE35/NAE45 Installation Instructions (Part No. 24-10050-6)
Installation and Specifications of the NAE45 or NAE35
NCE25 Installation Instructions (Part No. 24-10143-63)
Installation and Specifications of the NCE25
Metasys® System Field Equipment Controllers and Related
Products Product Bulletin (LIT-12011042)
Specifications of the Metasys® System Field Controllers
FAC2611 Advanced Application Field Equipment Controller
Installation Instructions (Part No. 24-10143-187)
Installation and Specifications of the FAC Series
Controllers
FAC2612-1 Advanced Application Field Equipment Controller
Installation Instructions (Part No. 24-10143-195)
FAC2612-2 Advanced Application Field Equipment Controller
Installation Instructions (Part No. 24-10143-233)
FAC3611 Advanced Application Field Equipment Controller
Installation Instructions (Part No. 24-10143-470)
FEC16 Field Equipment Controller Installation Instructions (Part
No. 24-10143-136)
Installation and Specifications of the FEC16 or FEC26
FEC26 Field Equipment Controller Installation Instructions (Part
No. 24-10143-144)
IOM2721 Input/Output Module Installation Instructions (Part No.
24-10144-149)
Installation and Specifications of the IOM Series
Controllers
IOM3721 Input/Output Module Installation Instructions (Part No.
24-10144-130)
IOM3731-0A Input/Output Module Installation Instructions (Part
No. 24-10144-165)
IOM17 and IOM27 Input/Output Module Installation Instructions
(Part No. 24-10144-76)
Installation and Specifications of the IOM17, IOM27,
IOM37, or IOM47
IOM37 Input/Output Modules Installation Instructions (Part No.
24-10144-84)
IOM47 Input/Output Module Installation Instructions (Part No.
24-10144-92)
3MS/TP Communications Bus Technical Bulletin