Aural Alerts

Serial Studio can sound its alarms. A dataset that crosses into a Warning or Critical alarm band, or a Warning or Critical notification posted from a script or the API, becomes an alarm point that is heard first and read second. The behaviour follows two published standards rather than an ad-hoc scheme:

ISA-18.1 (Annunciator Sequences and Specifications) for the state machine, its sequences A, M and R with or without option 4 (no lock-in), and the four operator actions: Acknowledge, Silence, Reset and Test (Serial Studio adds Clear).
IEC 60601-1-8 for the sound signatures: a pulse burst per priority, a fundamental between 150 Hz and 1000 Hz with at least four harmonics, and a repeat interval per priority.

Priorities use the flight-deck vocabulary: Warning, Caution and Advisory. Aural alerts are available in every build.

Priorities

Priority	Fed by	Bundled sound	Repeats
Warning	Critical alarm band (severity 3), Critical notification	One sustained 2.4 s tone (car-cluster buzzer)	Every 5 s (2.5 s to 15 s) until acknowledged, silenced or the condition clears
Caution	Warning alarm band (severity 2), Warning notification	Three-pulse burst	Every 10 s (2.5 s to 30 s) until acknowledged, silenced or the condition clears
Advisory	Info notification	Single pulse	Once, only while nothing else sounds

A dataset's alarm bands alert only when a widget that draws them is configured for it: the dataset has a Bar, Gauge or Meter widget or is shown in the LED Panel, and Hide on Dashboard is off, or the dataset belongs to a Bar Panel group. The widget does not have to be on screen. Bands on any other dataset stay in the project file but raise no alarm point and post no notification (see Alarm bands). A dataset with Suppress Alarms on (Project Editor, Widget Settings) keeps its bands on screen but never alerts. An Alarm Deadband on the dataset holds the active band until the value has left it by that margin, so a reading hovering on a threshold raises one point rather than one per frame; a step into a more severe band is never held back.

Info and OK alarm bands never alert. The Problems and System notification channels are the application's own diagnostics and never become alarm points. The alarm-band monitor's own notifications are recognised by their origin, never by their channel name, so a script or API client may post on any channel it likes — including one named "Alarms" — and still raise a point, in every interface language.

Alarm points and sequences

An alarm point is one dataset's alarm-band state, or one notification identified by its channel and title. Each point is in one of four states: Normal, Alert (active, unacknowledged: the annunciator flashes and the burst repeats), Acknowledged (active, steady, silent) or Return-to-normal (the condition cleared but the point waits for Reset).

The sequence decides what happens when a condition returns to normal:

Sequence	Return to normal after Acknowledge
A (automatic reset)	The point disappears.
M (manual reset)	The point stays in Return-to-normal, steady and silent, until Reset.
R (ringback)	As M, and a distinct two-pulse ringback sounds at the Caution interval until Reset or Silence.

Each sequence comes in two forms, and the form decides what happens when the condition clears before anyone acknowledged:

Form	Momentary alarm (clears before Acknowledge)
A-4, M-4, R-4 (ISA-18.1 option 4, no lock-in; A-4 is the default)	The audible stops the moment the value leaves the band, like an oil-pressure warning that goes quiet once the engine is running. A-4 drops the point; M-4 and R-4 park it in Return-to-normal until Reset.
A, M, R (plain, lock-in)	The point keeps sounding and flashing until acknowledged, so a dip that lasted two seconds is never missed. The sequence's after-Acknowledge rule then applies.

A notification point clears when a Resolved: <title> Info event arrives on the same channel, which is what notifyClear() and notifications.resolve post.

The sequence is an app preference (Preferences > Sounds) that a project may override (Project Editor > Project Summary > Settings > Alarm Sequence). In the project file and the API it is the code string: A-4, A, M-4, M, R-4 or R.

The master annunciator

A bell sits at the right end of the dashboard taskbar tray at all times. While any point is active its icon takes the colour of the highest active priority and shows the number of unacknowledged points; it flashes fast while anything is unacknowledged, slowly while a ringback is pending, and holds a steady colour when Reduce Motion is on. Clicking the bell opens the alarm panel: the active points, newest first (click one to jump to its widget), and the Acknowledge, Silence, Reset, Clear, Test and Mute actions. Right-clicking the bell acknowledges.

Action	What it does	Shortcut
Acknowledge	Every alerting point becomes Acknowledged; the audible and the flash stop.	Ctrl+Shift+A
Silence	The audible stops; points stay unacknowledged and keep flashing. A new point, or a point rising in priority, re-sounds (reflash).	Ctrl+Shift+H
Reset	Return-to-normal points go Normal (sequences M and R).	Ctrl+Shift+R
Clear	Drops every point from the list, acknowledged and alerting ones included. A point still inside its band comes back on the next transition.	Panel only
Test	Plays Advisory, Caution, Warning and Ringback in turn and walks the annunciator through each priority. No point is created.	Ctrl+Shift+T
Mute	Silences every alarm and event sound without touching the point table. Persists across restarts and shows on the annunciator.	Ctrl+Shift+U

At most one alarm sound plays at a time: the highest priority among unsilenced alerting points. When that priority is fully acknowledged or silenced, the next lower alerting priority takes over. Ringback plays only when nothing is in Alert.

Disconnecting on purpose returns every point to Normal without ringback; the Disconnected event sound plays instead. An unrequested link drop is different: the audible stops for the outage, but the point table is held — acknowledged points stay acknowledged, and when the link recovers, a dataset still in the same alarm band picks its point back up (an unacknowledged one resumes sounding, an acknowledged one stays quiet). Unacknowledged notification points are dropped at the loss, since the script that raised them cannot clear them across the outage. Opening a project or starting the application never sounds, and changing a preference only plays the (off-by-default) UI feedback events.

Preferences > Sounds

Enable Sounds (off by default; nothing plays until it is turned on), Mute, Volume, Output Device (system default or any output the OS lists). If the selected device disappears, sounds continue on the system default, the Problem Center reports the lost device, and output returns to it when it comes back. While sounds are disabled and the loaded project defines alarm sounds or alarm bands that can alert, the taskbar bell dims and the Problem Center says the alarms will be silent — a project full of alarms can never run mute without a visible hint.
Sequence (ISA-18.1): A-4 (default), A, M-4, M, R-4 or R.
One row per alarm signal (Warning, Caution, Advisory, Ringback): the WAV file (empty means the bundled sound), a browse button, a play button and a clear button. Warning and Caution also carry their repeat interval.
One row per application event, each with an enable switch: Connected, Disconnected, Link Lost, Reconnected, Export Finished, Recording Started, Recording Stopped, Error Dialog Shown, Button Pressed, Toggle Changed. Toggle Changed covers switches, radio buttons, checkboxes, combo box selections and spin box edits; Button Pressed covers buttons, the Preferences and console annotation tabs, and Project Editor tree clicks. Button Pressed and Toggle Changed are off by default. Event sounds play on their own lane, are lowered by 12 dB while an alarm sounds, and never delay an alarm burst.
Test and Reset to Bundled Sounds.

Any PCM WAV file works: 8, 16, 24 or 32-bit integer or 32-bit float, mono or stereo, 8 kHz to 96 kHz, at most 10 s. A file that fails to decode is refused with the reason and the slot keeps its previous value. Every configured sound is decoded when it is picked or when the application starts, so playing one performs no file access.

Project overrides

Two overrides travel with the project file:

Per alarm band. The Alarm Bands editor has a Sound column: pick a WAV to play instead of the priority default when the value enters that band. In the project file this is the band's sound key (see Alarm bands).
Per notification channel. Project Summary > Settings > Channel Sounds maps a channel name to up to three files, one per priority. Stored under the project's sounds object together with the sequence override:

"sounds": {
  "sequence": "M",
  "channels": {
    "Engine": { "warning": "sounds/horn.wav", "caution": "sounds/chime.wav" }
  }
}

A relative path resolves against the project file's folder, so a project folder can be shared with its sounds. A file that no longer exists falls back to the bundled sound and raises a Problem Center warning naming the path.

API

Command	Purpose
`alarms.state`	Sequence, mute, enable, highest priority, unacknowledged count, the sounding burst (`priority`, `file`, `burstStartedMs`, `burstCount`) and every active point (`kind`, `title`, `channel`, `priority`, `state`, `silenced`, `sinceMs`).
`alarms.acknowledge`, `alarms.silence`, `alarms.reset`, `alarms.clear`, `alarms.test`	The operator actions.
`alarms.setMuted`	`muted: true
`alarms.getProjectSounds`, `alarms.setProjectSounds`	Read or replace the project's `sounds` object; the setter validates every path and returns the rejected ones.

A headless session (--headless) runs the state machine and answers these commands without an audio device.