Control is useful only when it remains understandable

A radio-control system must do more than send successful commands. It must coordinate multiple applications, protect critical transmit operations, recover from expected interruptions and provide enough information to understand failures.

CAT4OM keeps these responsibilities in the central service so every client and integration benefits from the same rules.

One active controller at a time

Several native clients can connect to a radio group and receive live state, but only one client holds write ownership. Monitoring applications remain informed without being allowed to compete for the CAT connection.

When another identified client requests ownership, CAT4OM transfers the active role and broadcasts an ownership-change event. Interfaces can immediately enable or disable their write controls to reflect the new station authority.

A rigctl connection uses a separate exclusive claim for the target radio. Native clients continue seeing state updates while mutating requests are rejected until the external-control session releases the radio.

Transmit-safety lock

PTT and return-to-receive commands are safety-critical. CAT4OM applies conservative server-side rules while a radio is known to be transmitting.

• Ownership transfer is frozen while any radio in the group is in TX. The client that keyed the transmitter remains responsible for unkeying it.
• On the transmitting radio, other mutating commands are rejected so CAT traffic cannot delay or displace the TX-off command.
• Read-only state requests remain available.
• The explicit command to disable PTT is always given priority.

These checks are enforced in the service rather than relying on every user interface to implement them correctly.

Failsafe return to receive

If the controlling client disconnects while a radio is transmitting, CAT4OM attempts to force the transmitting radios back to receive before control is passed elsewhere.

A per-radio transmit watchdog provides another layer of protection. When the configured carrier-time limit is reached, the service sends a PTT-off command. If the attempt is not confirmed, the watchdog retries until the state returns to receive.

CW operations that key the radio through supported CAT commands are included in the safety model, allowing the watchdog and command lock to remain active during CAT-controlled CW transmission.

These safeguards supplement proper station design and operating practice; they do not replace hardware protections or cover a transmission that the radio never reports to CAT4OM.

Capability and state validation

Before executing an operation, CAT4OM checks the relevant conditions: connection state, client authority, radio availability and whether the configured handbook defines the requested command.

Clients also receive capability information so they can avoid offering controls that are not supported. This two-sided approach creates a better interface while retaining authoritative validation in the service.

Connection monitoring and recovery

Radio and network connections can be interrupted by a powered-off device, a cable problem, a temporary network failure or a remote endpoint restart. CAT4OM exposes connection state and supports configurable reconnection behaviour.

Polling strategies track consecutive communication errors and can disconnect an unhealthy radio rather than continuing indefinitely with stale state. Push-oriented adapters report their own connectivity and state changes through the same service model.

Failures remain scoped wherever possible. A disconnected Radio Follower does not stop its leading radio. An error on one synchronization link does not propagate into another radio or client request.

Diagnostics and logs

CAT4OM provides several levels of visibility:

• service and group status;
• per-radio connection state;
• handbook and port discovery;
• connection tests for supported configurations;
• command diagnostics;
• application logs;
• detailed per-radio wire logs;
• Radio Follower status and error counters.

Wire logs help show the actual command and response flow for a specific device. Structured service logs provide the wider context—group lifecycle, connections, ownership and synchronization decisions.

Radio Follower records degraded outcomes such as mode substitution, unsupported modes, out-of-range frequencies, timeouts and command errors. These events remain visible without turning a secondary receiver problem into a failure of the main radio.

Predictable lifecycle behaviour

Groups provide a clear boundary for starting and stopping station resources. Dependencies are respected: leading radios start before followers, and stopping a leading radio stops its followers. Compatible automatic power control uses an ordered workflow during full group startup and shutdown.

Individual connection stops do not silently become physical power-off operations. This distinction helps operators and automation know exactly what each lifecycle request means.

Reliability through a single authoritative core

The value of CAT4OM’s safety model is consistency. Ownership, capability checks, state updates, transmit protection and diagnostics are not optional behaviours implemented differently by every client. They belong to the central radio service and apply to the whole station.

Explore remote station control · Explore multi-radio control