BACnet Routers: What Contractors Need to Know

bas networking

BACnet routers have been a staple in the BAS space for over a decade, but are you choosing the right one for your application?

Choosing the right router for the job can make or break performance. Below is a simple breakdown for contractors:

What is a BACnet Router?

A BACnet router connects two different BACnet networks — most commonly:
BACnet/IP to BACnet MS/TP (RS-485)

Key Points:

Routers forward BACnet to BACnet traffic.
They do not translate protocols — that’s a gateway’s job (BACnet -> Modbus, Lon, etc.)
Common use cases include:

Connecting front-end servers to MS/TP field devices
Bridging multiple BACnet/IP subnets
BBMD/Foreign Device communication between subnets/NAT’d networks

Learn More on Routers Routers

What Contractors Need to Know:

Type	Purpose
Router	BACnet -> BACnet only (e.g., BACnet/IP -> BACnet MS/TP). Forwards BACnet messages between networks; does not translate protocols.
Gateway	Translates between different protocols (e.g., BACnet -> Modbus, BACnet -> Lon). Used when devices speak different languages.
Proxy	Lets IP networks “see” MS/TP-only devices through a single router (slave-proxy capability). Useful for discovery/visibility of MS/TP nodes from BACnet/IP.

Typical Network Setup

Most jobs have a BACnet/IP supervisory controller or server on the front end and one or more MS/TP trunks in the field. Each MS/TP trunk terminates at a BACnet router.

MS/TP Design Basics

Keep device counts within recommended limits (±64 per segment).
Manage biasing and termination.
Split long/heavy trunks ? multiple routers = faster networks.

BBMD / Foreign Device

Required when your BACnet/IP crosses subnets or VPNs.
Always check how many BBMD entries the router supports.

Diagnostics Save Hours

A router with a web page showing live MS/TP traffic, baud rate settings, and statistics is a commissioning cheat code.

Security Matters Now & What to Look For

Password protection
HTTPS
Firmware updates
BACnet/SC support (next-gen secure BACnet)

Power & Mounting

24 VAC, 24 VDC, PoE — pick what fits your panel.
DIN rail is the standard.
Isolated MS/TP ports reduce noise and ground loops.

Features You Should Demand

Must-Haves

BTL listed
Web diagnostics
BBMD + Foreign Device support
Adjustable baud rates
Ongoing firmware support

Nice-to-Haves

Dual Ethernet / VLAN
Isolated MS/TP
AC / DC / PoE power options
Slave Proxy
Compact DIN footprint

Brands Stromquist Trusts

Contemporary Controls

BASrouter family = our go-to for everyday BACnet/IP ? MS/TP bridging.

Easy setup, stable performance
Dependable BBMD support
Workhorses that just run

KMC Controls

Practical and contractor-friendly—BAC-5051E blends reliability with simplicity.

Good diagnostics
Straightforward commissioning
No over-engineering

Loytec

High-end choice for enterprise/multi-building networks.

Dual Ethernet, strong BBMD
World-class diagnostics
Built for big/complex jobs

Johnson Controls CW-CVT Tool (not a router)

Portable MS/TP utility for commissioning benches and field testing.

Great for troubleshooting
Speeds up on-site validation

Quick Recommendations for Better Networks

Plan before you purchase.
Map your IP subnets and MS/TP trunks — design drives router count and placement.
Don’t overload trunks.
Long or heavy MS/TP segments slow everything down. Split them and add routers where needed.
Tune MS/TP.
Default poll timing is rarely optimized. Adjust settings based on the actual network.
Crossing subnets? Check BBMD.
Make sure your router supports the BBMD/Foreign Device entries you need.
Bring a field tool.
Keep a portable MS/TP commissioning tool (like CW-CVT) on hand — it’ll save you hours in startup.

Bottom Line: BACnet routers are the backbone of modern hybrid BACnet networks.