BASRT-B - BACnet Multi-Network Router

BASRT-B is an industrial BACnet Multi-Network Router with 1 Ethernet port and 1 MS/TP port.

The BAS Router BASRT-B provides stand-alone routing between BACnet networks such as BACnet/IP, BACnet Ethernet, and BACnet MS/TP-thereby allowing the system integrator to mix BACnet network technologies within a single BACnet internetwork. There are two physical communication ports on the BAS Router. One is a 10/100 Mbps Ethernet port and the other an isolated MS/TP port. Configuration is accomplished via a web page.

The MS/TP port offers an optically-isolated transceiver. It has a removable 3-pin terminal block for the EIA-485 connection. Logically, 255 devices can be addressed. Physically, the number of devices depends upon device loading. Up to 31 full-load EIA-485 devices can share the same MS/TP bus segment as the BAS Router. For half-load devices, there can be 62. All MS/TP standard baud rates are supported-from 9.6 to 76.8 kbps.

The Ethernet port offers a shielded RJ-45 connector. Through auto-negotiation and Auto-MDIX, it automatically matches connections to the attached equipment. Therefore, either straight-through or crossover CAT5 cable can be used for hook-up.

A resident web server allows for commissioning, and troubleshooting via a standard web browser. A reset switch is provided on the router to return the unit to the factory default IP address. 

Features:

• Versatile routing between:
• BACnet/IP and BACnet MS/TP
• BACnet Ethernet and BACnet MS/TP
• BACnet/IP and BACnet Ethernet
• BACnet/IP and BACnet Ethernet and BACnet MS/TP
• Two BACnet/IP networks
• 10/100 Mbps Ethernet with auto-negotiation and Auto-MDIX
• Optically isolated MS/TP port
• Web server for commissioning and troubleshooting
• Foreign Device Registration (FDR)
• DIN-rail mounting
• 24 VAC/VDC powered

Specification:

Ethernet Communications

• Compliance: IEEE 802.3
• Data rate: 10/100 Mbps data rate
• Physical layer: 10BaseT, 100BaseTX
• Cable length: 100 m (max)

MSTP Communications

• Compliance: ANSI/ASHRAE 135 (ISO 16484-5)
• Data rate: 9600, 19200, 38400, 76800 bps
• Physical layer: EIA-485
• Cable Length: 1200 m (max)

LEDs

• Power: Green = power OK
• Ethernet:
• Green = 100 Mbps
• Yellow = 10 Mbps
• Flashing = activity
• MSTP: Flashing Green - receive activity

Power

• 24 VDC ±10% 2 W or 24 VAC ±10% 4 VA 47–63 Hz

Envrionmental

• Operating temperature: 0°C to 60°C
• Storage temperature: -40°C to 85°C
• Relative Humidity: 10–95%, non-condensing

Mechanical

• Dimensions: 115 mm x 26 mm x 70 mm
• IP protection: IP30
• Mounting: TS-35 DIN Rail

Certificates:

• CE Mark; CFR 47, Part 15 Class A; RoHS
• UL 508 C22.2 No. 142-M1987

Manufacturer's warranty: 36 months

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BASRT-B is designed for clean BACnet internetworking without “virtual points”: it routes BACnet traffic between BACnet/IP, BACnet Ethernet and BACnet MS/TP so field devices remain visible with their native BACnet objects. This is the practical way to modernize mixed building estates—keep BACnet Ethernet where it still exists, add BACnet/IP at the supervisory layer, and connect MS/TP trunks for field controllers, while maintaining one consistent BACnet view for the BMS.

On the MS/TP side, BASRT-B uses an optically isolated EIA-485 transceiver with a 3-pin connector (+, –, and SC). The SC pin is not optional in an isolated design—SC must be connected to the MS/TP segment signal common to ensure reliable communication. This construction reduces the risk of damage from common-mode voltages and improves robustness in real electrical environments with long trunks and multiple panels.

For stable bus physics, BASRT-B provides internal EIA-485 bias and termination via accessible jumpers: pull-up/pull-down bias (604 Ω at U/D) and termination (130 Ω at T), with an effective 120 Ω termination when all jumpers are installed. This is consistent with BACnet MS/TP practice and makes BASRT-B a strong choice for end-of-line router placement in long segments (up to 1200 m physical cable length as specified for MS/TP).

In routed BACnet/IP architectures, BASRT-B supports BBMD concepts and Foreign Device Registration (FDR), enabling BACnet discovery and communication across multiple IP subnets when broadcasts are blocked by IP routers. Importantly, enabling BBMD only when needed helps preserve network performance—unnecessary BBMD operation can increase discovery attempts and impair traffic flow in the BACnet/IP internetwork.

From an operations standpoint, BASRT-B includes a front Reset IP switch to restore factory-programmed default IP/login parameters for access recovery. Default web credentials are admin / admin, which supports fast handover during commissioning and service, while the Security settings allow you to harden access once the router is placed in production.