AirCodec  ·  Unattended operation

When the studio goes away, the transmitter does not.

A codec at a transmitter site is not a thing anybody is sitting in front of at two in the morning. So it walks its own connection list, falls into emergency programming with a legal ID on the hour, drops the transmitter only if the audio is genuinely dead, keeps testing the studio quietly, and climbs back the moment the studio is stable — and tells the monitoring system every step of the way.

  • FallThree connections, in order, then local emergency audio.
  • HoldLegal ID at the top of the hour, played clean, with nothing under it.
  • Climb backQuiet tests above it; the moment one holds, it goes on air with no gap.

Emergency programming that still identifies on the hour

Every codec carries its own emergency programme, loaded on that box, for the day the studio goes away. Not a tone and not a loop of dead air — a rotation that sounds like a radio station, with the legal ID where the rule says it goes.

Top of hour LEGAL ID, PLAYED CLEAN nothing under it :00 :15 :30 :45
Bin 1
Legal IDsPlayed in the break after the song that is playing at the top of the hour — as close to the hour as practicable, at a natural break, the way the rule reads.
Bin 2
SweepersDropped between songs so the hour sounds produced rather than shuffled.
Bin 3
Songs and programmesRandom or in order, loaded from files on the PC — WAV, MP3, FLAC and the rest.
The AirCodec emergency audio dialog for codec 1: a play mode set to rotation of songs, sweepers and legal IDs with a two second crossfade, three libraries holding legal IDs, sweepers and songs each with a random tick, add and remove buttons, a copy to all codecs button, and a state row showing what is playing, what is next, the time until the legal ID and what is loaded Open full size
One dialog per codec, and a Copy to all codecs button when five sites want the same programming. The state row underneath says what is playing, what is next and how long until the legal ID.

Or one long file

A show, or a loop, with the legal ID forced at the hour: the file pauses, the ID plays, the file resumes exactly where it was.

One segue setting, not a playout system

Zero to five seconds, equal power, with tail detection — a cut that trails into silence leaves no hole, and a cold ending is not chopped. The operator sees one player, not two decks to learn.

Four ways in

The EMERGENCY AUDIO key, the Profile menu for when everything is dead and you just need it going, a slot in the connection list, or the list falling into it by itself.

It survives a reboot

A codec left with emergency audio loaded picks it straight back up when the PC restarts — which is exactly when you are least able to drive out and press a key.

The changeover log at the top of the emergency audio dialog, listing when the codec went to emergency audio because no connection in the list held, and when it came back to the link after the connection tested stable for five seconds, with the time spent on emergency Open full size
Every changeover, kept: when it fell to emergency programming and why, when it climbed back, and how long it was on emergency. Per codec or across all five, copyable straight into a report.

Emergency audio with no legal ID at the top of the hour is illegal audio. §73.1201 asks for identification at the beginning and end of each time of operation and hourly, as close to the hour as feasible, at a natural break — for as long as the station is operating. None of that pauses because the studio link died; the transmitter is still on. A bin of songs and sweepers keeps the carrier modulated and leaves the station unidentified, which is why AirCodec flags no legal ID loaded in red on the box and reports it over SNMP — so you find out before an inspector does.

A ladder it walks down, and climbs back up on its own

You give the codec three connections in the order you want them. It takes the first that connects. When one fails it moves down. When none of them holds it plays its own programming — and from there it keeps quietly trying the ones above, and goes back to the first that proves stable. Nobody has to be awake for any of it.

1ST Incoming — wait for a caller failed 2ND Press Box Comrex (SIP) failed 3RD Emergency audio On air no audio for 2 min → move down still nothing → emergency audio Testing the slots above, quietly return muted — none of it is heard Stable for 5 s → back on air, no gap

The same three slots can be any mix — a Direct link, a SIP call, an incoming slot that waits for a caller, a stream. Emergency audio does not have to be last; put it in a higher slot and the codec stops there instead.

Failed after no audio forHow long a slot may be silent before the codec gives up on it and moves down. Set it long enough to ride out a hiccup, short enough that a dead link does not sit there.
Stable afterHow long a recovered connection has to behave before the codec trusts it and goes back. This is what stops it bouncing between two bad links.
An incoming slot waits for a callerA slot set to Incoming holds the door open this long. Nobody calls, it moves on.
Test higher connections everyHow often, while on a lower slot or on emergency audio, it quietly tries the ones above. The return is muted during the test, so none of it reaches air.
Hold this listTick it and the codec runs the list now and again every time the app starts — so a machine that reboots at 4 a.m. comes back up on its own.
The connection list dialog: a hold-this-list tick box, three ordered slots with an incoming slot first, a SIP profile second and emergency audio third, and the timers for failed after no audio, stable after, how long an incoming slot waits, and how often higher connections are tested Open full size
The whole failover policy is one dialog — three slots and four timers. The line at the foot reads back what it is doing right now.

Relays: automation that reaches the other end of the link

A codec that only carries audio leaves half the job undone. AirCodec carries five contact closures each way on the same clock as the programme, so a cue fired at the studio lands at the far end in step with the audio it belongs to — not whenever the network gets round to it.

Studio AirCodec fires relay 2 Transmitter site AirCodec relay 2 closes Audio Closures — same clock 0 s 2 s 4 s 6 s 8 s relay 2 fired here — and it lands here Automation SportsCaster Pro One timeline for the audio and the closures, end to end.

Press for a pulse, hold for a hold. A closure history at both ends records every one, with the time.

Closures across the link

Five sent and five received per codec, the way the hardware codecs do it — so a remote can fire a cue at the studio and the studio can fire one back.

  • A press is a pulse; a hold is a hold
  • Carried in time with the audio, not down a side channel
  • The RELAYS label says whether they are going over the call at all
  • Click RELAYS on the readouts grid for the closure log instead of a graph

The board on the box

A standard eight-output FTDI USB relay board with its 12 V supply, driven by the codec at that site, with test keys in the dialog so you can prove the wiring before you leave.

  • Eight outputs for local automation
  • Reported over SNMP, including when the board goes missing
  • Relay board LOST is its own alert — the contact cannot fire and you find out

Watch the audio, drop the transmitter

Point a codec at its own output and it will take action on silence, with no human in the loop.

  • Silent for 5 s to 2 min, then fire — held, or a pulse of 0.5 to 5 s
  • On return: release the held relay, pulse another, or do nothing
  • Emergency audio counts as audio — the transmitter stays up on it

Lose the internet, act on it

The link going away is itself a condition worth wiring to a contact. A site that must not sit there modulating silence can be taken off; a site that needs its local source brought up can be switched over.

  • Fire a relay to take a transmitter off when the programme is truly dead
  • Or to bring one up and switch to a local source
  • Every one of those moves is written to the activity log and reported over SNMP

With SportsCaster Pro in the field, the same five closures run between the announcer's rig and the studio — so a talent cue, a break marker or a roll command travels the same path as the audio and arrives on the same clock. No second circuit, no separate control link, nothing else to pay for.

What it runs on, and what it does when nobody is there

Requirements

  • Windows 10 or 11
  • A sound card with a line input and a line output. ASIO is not required. A multi-channel card — Livewire, WheatNet or any multi-channel WDM or ASIO interface — gives each codec its own pair.
  • A network connection.
  • For the transmitter-site contact: a standard FTDI-based USB relay board with its 12 V supply.

Unattended operation

  • Starts with Windows, optionally minimized, and auto-connects what was loaded
  • Re-arms its listeners and resumes emergency audio if it was left loaded
  • Watches its own audio engine as a separate process, reports its build and protocol level, and flags a stale engine in red
  • Updates itself from a signed manifest, with the installer run for you
The Windows tab of AirCodec settings, with tick boxes for starting AirCodec when Windows starts on installed builds and for starting minimized, above a save settings button Open full size
Two tick boxes are the whole unattended-rack setup: AirCodec comes up after logon, registers by itself, and stay-connected profiles come back on their own.

Audio is picked per codec. Each codec has its own line input and line output in its settings, so on a two-channel card they share the one pair — and on a multi-channel card every codec gets its own, and all five can carry their own site at once.

AirCodec

Put one at the transmitter site.

A PC, a sound card and a relay board, and the site rides out a studio failure on its own — identifying on the hour, testing quietly, and climbing back without a drive out at two in the morning.

Ask about AirCodec See pricing

$499.99 per codec · run up to five on one PC

More on AirCodec

Connecting other codecs Security Compatibility Audio codecs On screen SNMP and monitoring Pricing