Using Ruby's GPIO Ports to Trigger External On-Air Lights and Signage

On-air lights and signage are essential visual indicators in any radio studio. Whether a broadcaster is in a heritage studio in Sydney or a modern facility in Melbourne, the team needs a reliable way to show when microphones are live. The Australian Communications and Media Authority encourages broadcasters to give clear signals to talent and guests, and a well-wired on-air lamp is a simple compliance tool.

Ruby mixing consoles from Lawo include built-in GPIO ports on the rear panel. These ports allow the console to send or receive low-voltage signals to external devices. For Australian broadcasters, this means a Ruby can drive a relay, a wall lamp, or a corridor sign without extra middleware.

GPIO stands for General Purpose Input/Output. Each pin on the Ruby can be configured independently. In output mode, a pin can switch an LED or drive a relay coil that handles the higher current needed by an industrial lamp. The console's internal logic drives these pins whenever the studio changes state.

Major Australian networks such as the ABC and stations running triple j have used physical on-air indicators for decades. The same approach translates cleanly to networked studios, and Ruby makes the integration straightforward through its GPIO ports.

Hardware layout and electrical considerations

The GPIO pins on a Ruby are exposed through a multi-pin connector on the back of the frame. Each pin is rated for low-voltage DC loads. For most radio installations in Brisbane or Perth, a 12V or 24V relay sits between the pin and the actual lamp to handle higher current safely.

Australian practice under AS/NZS 3000 requires isolation between low-voltage control circuits and mains-powered devices. A relay or opto-isolator is the standard way to meet that requirement and protects the console from voltage spikes on the field side.

Cable runs to a signage location should use shielded cable to keep electrical interference away from the audio path. In media precincts such as Sydney Olympic Park, existing cable trays make the wiring job straightforward.

Configuring GPIO pins for on-air tally

Ruby firmware allows engineers to map GPIO pins to specific console states. The on-air tally, mic-live tally, and talkback activity can each drive a separate pin. Engineers configure the mapping through the console's setup menus.

Once a Ruby is rack-mounted in a machine room, engineers often want to verify the tally behaviour without climbing into the studio. The page on Remote control of Ruby consoles from a tablet for studio diagnostics describes how to inspect GPIO states remotely, which is helpful when commissioning a new lamp.

After configuration, the console sends a contact closure whenever the studio goes to air. The same closure can feed a relay board that powers multiple devices in parallel, from a single wall lamp to a bank of corridor signs.

Integrating with external signage and displays

A GPIO closure from the Ruby starts the signalling chain. The closure typically feeds a relay board or small PLC that drives the actual signage hardware. In a small studio, a single 12V relay is often enough to switch a classic red on-air lamp.

For larger facilities hosting live events, the signage work often involves specialist integrators with experience in lobby displays. Teams that handle signage display control for live events can translate the GPIO closure into anything from a wall sign to a full LED video panel.

Smaller commercial stations often use off-the-shelf LED drivers or industrial illuminated signs. The Ruby GPIO acts as the switch, and the downstream hardware handles the visual side. This keeps integration light and maintenance low.

Working with RƎLAY and software tally

Stations that run RƎLAY virtual radio tools alongside a physical Ruby can share tally information across the network. The RƎLAY VRX software reads on-air state over IP and can pass it to signage servers that drive screens in reception areas of a Melbourne or Perth building.

This means a single tally source feeds both the GPIO-driven hardware lamps and the software-based lobby displays. A presenter working from a remote location can still trigger an on-air lamp in the main studio over the network, which helps hybrid workflows common across Australian radio.

Practical workflows in Australian stations

Major broadcasters in Sydney have used wall-mounted on-air lamps for decades. They sit outside each booth and inside producer cubicles so that everyone in the corridor can see at a glance which booth is live.

Regional stations in Hobart and Adelaide use similar setups but rely more on GPIO-driven corridor signs to direct foot traffic away from active studios. Cricket coverage from the MCG or the SCG benefits from clearly lit booths, since producers and statisticians all move between rooms during play.

Under the operational practice guidelines issued by ACMA, broadcasters are encouraged to provide clear indicators to talent and guests. A GPIO-driven lamp is one of the simplest and most reliable ways to meet the expectation without adding extra screen clutter.

Method	Wiring	Latency	Best for
GPIO direct closure	Single twisted pair	Under 50 ms	Single booth or studio
Relay bank	Multi-core cable	Under 50 ms	High-current signage
Networked IP tally	Cat5e or Cat6	100-300 ms	Multi-room facilities
Software tally	Ethernet or Wi-Fi	200-1000 ms	Distributed displays

The takeaway for Australian broadcasters is that Ruby's GPIO ports give a low-latency way to drive on-air lamps, lobby signs, and external displays from a single console. When combined with RƎLAY VRX, the tally signal can travel from the hardware console to software-driven signage across a building or across the country. Studios that need clear visual indicators for talent, producers, and guests will find that GPIO remains one of the simplest pieces of the broadcast chain, and a well-wired on-air lamp still earns its place next to every microphone in the country.