Ports & Adapters
Ports
A port in OmniBus is one data source:
- A serial device — a USB-to-RS-485/RS-232 adapter or on-board UART, e.g.
/dev/ttyUSB0,/dev/ttyAMA0. - Or, for network-transport adapters (the Modbus TCP client), a logical port with no serial device that connects out over the network.
Each port carries serial settings (baud rate, data bits, parity, stop bits) appropriate to the bus, an assigned TCP port and MQTT prefix, and the adapter that decodes its traffic.
Adding a port
From the Ports dashboard:
- Click Add Port.
- Select the serial device (OmniBus lists what it sees) — or choose a network-transport adapter.
- Pick the protocol. This selects the adapter.
- Set the serial parameters for the bus (baud/parity/etc.).
- Toggle the outputs you want (TCP, MQTT, REST, webhooks).
- Save. The adapter starts immediately.
You can edit, disable, or remove a port at any time from its card on the dashboard.
Adapters
The adapter is the protocol brain of a port. OmniBus ships these:
| Adapter | Protocol | Notes |
|---|---|---|
raw | Raw byte stream | Pass-through; optional throttling. |
modbus-rtu | Modbus RTU | master (RTU↔TCP gateway + poller) or slave (register map). |
modbus-tcp-client | Modbus TCP (client) | Polls upstream TCP servers; no serial device. |
bacnet-mstp | BACnet MS/TP | MS/TP master bridging to BACnet/IP; or sniffer. |
osdp | OSDP (access control) | ACU polling readers/keypads; Secure Channel (beta). |
mbus | M-Bus (metering, EN 13757) | Master that initializes and reads meters. |
dnp3 | DNP3 (IEEE 1815) | gateway (serial↔TCP) or outstation. |
n2 | Johnson Controls Metasys N2 | sniffer (default) or single-master polling. |
jandy | Jandy AquaLink RS pool bus | Decoder + RSSA-over-TCP + AllButton emulator. |
pentair | Pentair RS-485 pool bus | Status decode and transmit. |
Each adapter has its own configuration panel in the UI and its own page in the Protocols section.
How an adapter is wired
Internally every adapter implements the same small surface, which is why behavior is consistent across protocols:
- It receives bytes from the serial line and decodes them.
- It receives bytes from a TCP client connected to that port's TCP server.
- It receives MQTT messages on the topics it subscribes to.
- It exposes REST actions for synchronous control.
- It emits parsed events, which OmniBus routes to MQTT and webhooks in one step.
The result: enable any combination of outputs on a port and the same decoded event reaches all of them.
Serial wiring notes
- Use a proper RS-485 transceiver and match A/B polarity to the bus. There is no software pin-reversal — wire it correctly at the converter.
- Match baud/parity/stop bits to the field devices. The protocol pages list the usual defaults (e.g. BACnet MS/TP commonly 38400 8N1, Jandy 9600 8N1).
- Many buses are single-master. Read each protocol page before enabling an active/master mode on a live trunk — putting a second master on a single-master bus disrupts it.