HVAC Bridge Board — the on-site automation server.
An IP65 industrial gateway that integrates with existing VRV / VRF, chillers, and VAVs over BACnet IP and MODBUS RTU, and exposes the supervisory plane to the mobile and web application. Edge logic continues to operate when backhaul is interrupted. Signed OTA firmware updates. Galvanic and serial isolation on every external port.
South-side protocols, north-side supervisory plane.
The HVAC Bridge Board is AmbiAutomation's on-site automation server. It communicates with HVAC equipment over the protocols that equipment already exposes (BACnet IP, MODBUS RTU), and presents the supervisory plane to the mobile and web application over encrypted HTTPS / JSON.
- Integration with VRF / VRV systems, chillers, and VAVs
- BACnet IP and MODBUS RTU on the equipment side; HTTPS / JSON on the supervisory side
- Edge-resident schedules and alarms continue operating during backhaul outage
- Building-network telemetry for preventive maintenance and audit
- Signed OTA firmware updates; authenticated end-to-end
HVAC Bridge Board — technical reference.
| Form factor | Compact panel-mount |
|---|---|
| Enclosure | IP65 |
| Real-time clock | Integrated |
| Network | DHCP or static IP |
| LEDs | Power (red); Ethernet link (orange / green); GPRS (red / green) |
| User interface | Web browser and mobile application |
| Power | 8–26 VAC, 50/60 Hz from controls panel (< 500 mA); optional 12 VDC adapter |
| Interfaces | RS232, RS485, Ethernet, Wi-Fi |
|---|---|
| Protocols | BACnet IP, MODBUS RTU, MODBUS TCP/IP, JSON / HTTP, proprietary RS232 |
| Backhaul | Wi-Fi, Ethernet, GPRS / CAT 1, NB-IoT (all encrypted) |
| Cellular bands | Quadband GPRS (850/900/1800/1900 MHz); CAT 1 bands 3, 7, 20, 21 (Jio, Airtel, Vodafone, Idea compatible) |
| SIM | Onboard SIM slot; external omnidirectional antenna |
| Connector | RJ-45 (Cat 5 UTP) |
|---|---|
| Standard | IEEE 802.3i 10/100 BASE |
| Isolation | 1.5 kV galvanic |
| Max cable | 100 m |
| Protocols | JSON, HTTP, BACnet IP, MODBUS TCP/IP |
| Connector | 5.08 mm 2-port terminal block |
|---|---|
| Standard | EIA-485-A 2-wire |
| Isolation | 15 kV serial |
| Nodes | Up to 64 |
| Baud | 2400 / 4800 / 9600 / 19200 / 57600 / 115200 bps |
| Protocol | MODBUS RTU |
Where the on-site server is deployed.
Building management
Centralised control over distributed HVAC fleets. Lighting integration where lighting controllers expose BACnet or MODBUS interfaces. North-side API for facility-management platforms.
Energy management
Scheduled setpoint caps, occupancy-aware operating modes, runaway-unit detection, demand-response signal handling where DR feeds are available. Tariff-period scheduling.
Preventive maintenance
Network-vitals telemetry per zone and per unit. Drift alarms, comms-loss alarms, run-hour tracking. Annual Maintenance Contract (AMC) compatible.
Request the full HVAC Bridge Board datasheet.
Send a short note with your project context — building size, HVAC OEM, target outcomes — and our engineering team will return the latest datasheet plus a deployment recommendation within one business day.