The Contemporary Controls BASRTSX-B BASrouterSX is a high-performance BACnet multi-network router for demanding building automation networks where security, scale, and serviceability matter. The BASRTSX-B routes between BACnet/IP, BACnet MS/TP, and BACnet Ethernet (ISO 8802-3) in any combination, and adds the advanced features that the entry-level BASrouter lacks: HTTPS / SSL encrypted web configuration, 50-entry BBMD and 147-entry Foreign Device Registration tables, MS/TP frame capture for offline analysis in Wireshark, MS/TP slave proxy with auto-discovery, Allowlist IP security filtering, MS/TP Backbone and Backward Routing for complex topologies, and externally-accessible DIP switches for bias and termination - no case opening required for mid-span installation. The BASRTSX-B mounts on standard 35-mm DIN-rail in a metal enclosure rated -40°C to +75°C, ideal for permanent installation in BAS control panels.
› Enterprise-Grade Security & Scale
The BASRTSX-B secures all web-based configuration through HTTPS / SSL encrypted communication and requires the user to configure a unique 8-63 character username and password on first login (no default admin / admin credentials). The Allowlist feature restricts BACnet communications to specified IP addresses, and the BBMD table holds up to 50 entries with 147 FDR registrations - 10x and 29x larger than the BASRT-B respectively.
› Pro-Level MS/TP Diagnostics
The BASRTSX-B continuously captures MS/TP frames into a buffer that can be downloaded as a .pcap file and opened in Wireshark - giving you protocol-level insight into token passes, data exchanges, and errors without specialized hardware. MS/TP slave devices (which can't participate in token passing) are made fully addressable through Manual Slave Address Binding or Automatic Slave Discovery, with the BASRTSX-B acting as their proxy.
| BASRTSX-B Specifications | |
|---|---|
| Model | BASRTSX-B |
| Manufacturer | Contemporary Controls |
| Product Family | BASrouterSX / BASautomation |
| Mounting | TS-35 DIN-rail (35 mm), metal enclosure |
| Networks Routed | BACnet/IP, BACnet Ethernet (ISO 8802-3), BACnet MS/TP (in any combination) |
| BACnet Profile | BACnet Router (B-RTR) and BACnet Broadcast Management Device (B-BBMD) |
| BBMD Table Size | 50 entries (Broadcast Distribution Table) |
| FDR Table Size | 147 entries (Foreign Device Registration) |
| Web Configuration | HTTPS / SSL encrypted resident web server |
| Authentication | User-configured username (8-63 chars) + password (8-63 chars + special chars) on first login - no default credentials |
| Security Features | Allowlist (IP-based access filtering), HTTPS web config, user-configured credentials |
| MS/TP Wireshark Capture | Built-in frame capture buffer, downloadable as .pcap file |
| MS/TP Slave Proxy | Manual Slave Address Binding + Automatic Slave Discovery |
| MS/TP Backbone Routing | Yes |
| Backward Routing | Yes |
| Ethernet Port | 1 × Shielded RJ-45, 10/100 Mbps, IEEE 802.3, Auto-Negotiation, Auto-MDIX |
| Ethernet Cable Length | 100 m (max) CAT5 |
| MS/TP Port | 5-pin removable terminal block, optically-isolated EIA-485 |
| MS/TP Standard | ANSI/ASHRAE 135 (ISO 16484-5) |
| MS/TP Baud Rates | 9600, 19200, 38400, 57600, 76800, 115200 bps (selectable) |
| MS/TP Cable Length | 1200 m (max); 1000 m (max) at 115.2 kbps |
| MS/TP Devices Supported | Up to 31 full-load (or 62 half-load) per segment, 254 total addresses |
| MS/TP Bias & Termination | Externally-accessible DIP switches (no case opening required) |
| Power Input | 24 VDC ±10%, 3 W or 24 VAC ±10%, 6 VA, 47-63 Hz |
| Power Connector | 4-pin removable terminal block (HIB / HI / COM / chassis); 16-18 AWG; redundant power input supported |
| Reverse-Polarity Protection | Yes |
| LEDs | Power, Status, 2 × Ethernet (link status / data activity / data rate), 2 × EIA-485 (Tx and Rx data) |
| Reset | Front-mounted Reset IP button (10-second hold restores factory default IP and clears credentials) |
| Default IP / Subnet | 192.168.92.68 / 24 |
| Operating Temperature | -40°C to +75°C (-40°F to +167°F) |
| Storage Temperature | -40°C to +85°C |
| Humidity | 10-95%, non-condensing |
| Enclosure | Metal case |
| Compliance | UL 508 Listed, c-UL Listed (CSA C22.2 No. 142-M1987); CE Mark; CFR 47 Part 15 Class A; RoHS |
| Warranty | 5-year manufacturer warranty |
BASRTSX-B Product Documentation
BASrouterSX Installation Guide BASrouter Family Application Guide (11 Routing Examples) Successful BASrouter Installation & Operation (covers BASrouterSX) Troubleshooting BACnet Networks (BASrouterSX Status Screen)BASRTSX-B Application Notes & Compatibility
Using a BASrouter with an Alerton Controller Using a BASrouter with a Honeywell Spyder Controller Using a BASrouter with a Centraline Lynx Controller Using a BASrouter with a Trend IQ Controller Adding Cube I/O Modules to BACnet Spyder Controllers Using a BASrouter to Offload Your JACEBASRTSX-B - Frequently Asked Questions
What is the difference between the BASRTSX-B (DIN-Rail) and the BASRTSX-B/P (Panel Mount)?
The BASRTSX-B and BASRTSX-B/P are functionally identical - same firmware, same routing capability, same HTTPS web interface, same BBMD/FDR/Allowlist/Wireshark/Slave-Proxy features, same hardware electronics, same warranty. The only difference is the enclosure mounting style: the BASRTSX-B mounts on standard 35-mm DIN-rail (TS-35) and is the right choice for a typical BAS control panel; the BASRTSX-B/P uses a panel-mount metal enclosure for installation in cabinets, plenums, or other locations where DIN-rail is not available. Choose based on your enclosure constraint - the configuration, performance, and BACnet behavior are exactly the same.
What is the difference between the BASrouterSX (BASRTSX-B) and the BASrouter (BASRT-B)?
The BASRTSX-B is Contemporary Controls' high-performance BACnet router and a meaningful upgrade from the entry-level BASRT-B. Key differences: HTTPS / SSL encrypted web configuration (vs unencrypted HTTP on BASRT-B); 50 BBMD entries + 147 FDR entries (vs 5 / 5 on BASRT-B); built-in MS/TP frame capture for Wireshark (not available on BASRT-B); MS/TP slave proxy with auto-discovery (not on BASRT-B); Allowlist IP security filtering (not on BASRT-B); MS/TP Backbone and Backward Routing (not on BASRT-B); externally-accessible DIP switches for bias / termination (vs internal jumpers requiring case opening on BASRT-B); higher 115.2 kbps MS/TP baud rate (vs 76.8 kbps max on BASRT-B); user-configured credentials on first login (vs default admin / admin on BASRT-B); higher-performance processor and more memory. Choose the BASRTSX-B for large, security-conscious, or diagnostically-demanding installations; choose the BASRT-B for cost-sensitive single-subnet projects.
Is the BASRTSX-B the replacement for the discontinued BASrouterLX?
Yes. The BASrouterSX product line (including the BASRTSX-B) is Contemporary Controls' current high-performance BACnet router and is the active replacement for the discontinued BASrouterLX (BASRTLX-B and BASRTLX-B/P). The BASrouterSX adds HTTPS / SSL encrypted web configuration, the Allowlist security feature, externally-accessible bias / termination DIP switches, and other enhancements over the legacy LX line, while preserving the 50-entry BBMD and 147-entry FDR table sizes that LX users relied on. If you previously specified a BASRTLX-B or BASRTLX-B/P, the BASRTSX-B is the modern equivalent.
What does HTTPS / SSL configuration mean for the BASRTSX-B?
The BASRTSX-B's built-in web configuration interface uses HTTPS (HTTP over SSL/TLS) instead of unencrypted HTTP. This means commissioning credentials, configuration changes, and diagnostic data are transmitted in encrypted form between your browser and the router, protecting them from network sniffing and meeting modern IT security policies that prohibit cleartext credentials on the network. On first login, you must configure a unique 8-63 character username and password (no factory default admin / admin), and the password supports special characters (~!@#%^+[]{}_) for strength.
How does the BASRTSX-B's MS/TP Wireshark capture work, and why is it useful?
The BASRTSX-B continuously captures MS/TP frames into an internal buffer. From the web interface, you can download the captured traffic as a standard .pcap file, then open it in Wireshark (free download from wireshark.org) to analyze token passes, data exchanges, retries, and errors at the protocol level. This is the same diagnostic approach Contemporary Controls' own engineers use, and it is enormously useful for troubleshooting intermittent MS/TP issues - mismatched baud rates, address conflicts, missing devices, marginal cabling - without needing dedicated MS/TP analyzer hardware. Wireshark includes a built-in BACnet decoder, so frames display in human-readable form with object types, properties, and values fully parsed.
What is MS/TP slave proxy and when do I need it?
BACnet MS/TP slave devices (typically simple sensors, low-cost actuators, or some legacy controllers) do not participate in MS/TP token passing - they only respond when explicitly polled by their MAC address. This makes them invisible to standard BACnet device discovery (Who-Is). The BASRTSX-B's slave proxy feature lets you register MS/TP slave devices either manually (Manual Slave Address Binding) or automatically (Automatic Slave Discovery), after which the BASRTSX-B responds on their behalf to BACnet/IP discovery requests. The result: your BAS head-end "sees" slave devices in the device list and can ReadProperty / WriteProperty them as if they were standard BACnet devices.
What is the Allowlist security feature on the BASRTSX-B?
Allowlist is an IP-based access filter built into the BASRTSX-B's firewall layer. You specify which IP addresses (or ranges) are permitted to communicate with the router, and all other incoming BACnet/IP traffic is dropped. This is useful in environments where the BAS network shares physical infrastructure with other systems and you want to ensure only sanctioned BAS clients (your head-end, your BBMD partners, your commissioning laptops) can interact with the router. Combined with HTTPS web configuration and user-configured credentials, Allowlist gives the BASRTSX-B a meaningfully tighter security posture than the entry-level BASRT-B.
When do I need the higher 115.2 kbps MS/TP baud rate that the BASRTSX-B supports?
For most BAS deployments, 38.4 kbps or 76.8 kbps is the right choice and remains the most widely-supported speed across field controllers from Honeywell, Distech, Reliable Controls, Alerton, and others. The 115.2 kbps option on the BASRTSX-B is useful when (a) every controller on the segment supports 115.2 kbps and you want to maximize polling throughput, or (b) you are building a high-density MS/TP backbone with many devices and need the additional bandwidth headroom. Note that at 115.2 kbps the maximum MS/TP cable length drops from 1200 m to 1000 m, and not all field controllers support this rate - verify your devices' published baud rate options before committing the segment.
What are MS/TP Backbone and Backward Routing, and when would I use them?
These are advanced BACnet routing features for complex multi-segment topologies. MS/TP Backbone lets you treat one MS/TP segment as a backbone connecting multiple BAS subsystems, with the BASRTSX-B routing BACnet traffic across it as if it were Ethernet. Backward Routing allows BACnet messages to be returned along the same path they took outbound, which is critical for response routing in topologies with multiple potential paths. Most single-router installations will not need either feature, but they become important when integrating into existing multi-router internetworks or when retrofitting BAS expansion onto sites with established MS/TP infrastructure.
Can I share a 24 VAC transformer between the BASRTSX-B and my MS/TP controllers?
Yes - with one important caveat. The BASRTSX-B uses a half-wave rectified low-voltage power supply, so it can share a 24 VAC source only with other half-wave rectified devices (which is the vast majority of BAS field controllers, including Honeywell Spyder, Centraline Lynx, Alerton, and most Cube I/O modules). Do NOT share an AC source with full-wave rectified devices - mixing the two on a common transformer can damage equipment. The BASRTSX-B consumes 6 VA at 24 VAC or 3 W at 24 VDC. Verify total transformer VA capacity covers the combined load, and note that the BASRTSX-B also supports a redundant power input (HIB) for backup power schemes.
Do I need to open the BASRTSX-B to set MS/TP bias and termination?
No. Unlike the BASRT-B (which requires opening the case to access internal jumpers), the BASRTSX-B provides externally-accessible DIP switches on the front of the unit for bias and termination. For end-of-line installation, set both DIP switches ON to apply 120-ohm termination and fail-safe voltage bias. For mid-span installation (where the bus is terminated by other devices), set both DIP switches OFF. This makes the BASRTSX-B significantly faster to commission and easier to reconfigure if your bus topology changes.
Your BASRTSX-B BASrouterSX is backed by Contemporary Controls' five-year manufacturer warranty against defects in materials and workmanship from the original ship date. The BASRTSX-B is BACnet conformant per the published B-RTR (BACnet Router) and B-BBMD (BACnet Broadcast Management Device) Standardized Device Profiles, UL 508 Listed and c-UL Listed (CSA C22.2 No. 142-M1987) for industrial control equipment, CE marked, and RoHS compliant for use in commercial, industrial, and international BAS projects.
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- BACnet Routers
