Connect CAT4OM to the rest of the station
CAT4OM is designed to be used by more than its supplied desktop interface. Existing amateur-radio applications can connect through the built-in rigctl compatibility layer, while custom software can use the native JSON WebSocket protocol for richer control, management and live state.
These two integration surfaces serve different needs and can coexist within the same station.
Hamlib NET rigctl subset emulation
CAT4OM includes a TCP server that emulates the core commands of the Hamlib NET rigctl protocol. Compatible logging, digital-mode and station applications can connect directly to CAT4OM using a familiar network-radio interface.
The supported command subset covers essential operations such as:
- reading and setting frequency;
- reading and setting mode;
- reading and setting PTT;
- VFO selection;
- split control and related state.
A separate Hamlib or rigctld process does not need to be installed and should not be running for this CAT4OM endpoint. CAT4OM receives the rigctl request, passes it through its radio engine and translates it through the configured handbook.
Changes made through rigctl update the same authoritative radio state used by native clients. A CAT4OM interface can see a frequency change initiated by compatible third-party software, and Radio Follower can react to it without bridge-specific synchronization code.
To prevent concurrent write conflicts, a radio used by a rigctl session is claimed for that external control path. Native clients continue receiving its state but cannot issue competing mutating commands until the claim is released.
Native JSON WebSocket API
The native protocol provides access to the full CAT4OM model. It uses structured request, response, welcome, event, service-status and state-update messages over WebSocket.
Through the Control channel, an integration can:
- discover visible radios and their initial state;
- request or observe client ownership;
- read radio state;
- set frequency, mode, VFO, split, PTT, RIT/XIT and other supported controls;
- use CW or raw operations when the radio explicitly exposes them;
- receive live state and ownership events;
- inspect supported modes, VFOs and commands;
- run supported radio diagnostics.
Through the Management channel, an authorised tool can:
- inspect service, group and radio status;
- discover installed handbooks and available ports;
- read and update configuration;
- start or stop groups and radios;
- test compatible connections;
- perform supported radio power-on and power-off operations;
- monitor Radio Follower relationships and health.
Build adaptive integrations
An integration should not assume that every radio offers every operation. CAT4OM supplies runtime capability information so software can adapt to the selected model.
Before presenting or sending a control, a client can check connection status, ownership, available commands, supported modes, VFOs and command scope. One well-designed client can therefore work across many radios while presenting only valid choices.
Real-time event-driven workflows
CAT4OM pushes changes to connected clients. An integration can keep a receive loop open and react to updates rather than continuously querying the service.
This suits applications such as:
- desktop and web control panels;
- logging and digital-mode bridges;
- contest dashboards;
- station-health monitors;
- custom tuning or macro controllers;
- automated startup and shutdown workflows;
- hardware control surfaces;
- test and diagnostic tools;
- telemetry displays and remote panels.
Because commands from native clients, rigctl applications and the radio itself converge on the same state model, event-driven automation sees a coherent sequence of station changes.
Clear control ownership
Several native clients may connect and monitor a group, but only one holds write ownership at a time. An application can request ownership when the operator wants it to become the active controller. All connected clients receive an event when ownership changes.
Read operations remain available to monitoring clients. Write operations are validated by the service against ownership, radio capabilities, connection state and transmit-safety rules.
Language-independent by design
The native interface uses JSON over standard WebSocket connections. Integrations are not limited to .NET or to CAT4OM assemblies; they can be written in any language with suitable WebSocket and JSON support.
The integration manual documents the wire format, actions, state fields, errors and example flows. This lets developers treat CAT4OM as a standalone radio-control service rather than linking its internal implementation into their applications.