SBUS (digital UART)

SBUS is the digital RC protocol most modern receivers and flight controllers speak. Magic Box outputs it on the UART 3.5 mm jack (and on the dedicated UART pads on the motherboard).

Wire format: inverted UART, 100 kbps, 8E2. Up to 16 channels in one packet, plus a few digital flags (failsafe, frame lost). The widely supported default — if you’re not sure which digital protocol to pick, this is the safe answer.

Pick SBUS when your receiver or flight controller documentation lists “SBUS” as an input. That covers nearly all FrSky, FlySky, RadioMaster, and ExpressLRS receivers when wired to the SBUS pad.

Configure in the Web UI

Open the Web UI from your phone or laptop.
Go to Settings → Output protocol.
Pick SBUS.
Save. The change applies on next boot.

PPM keeps working at the same time on the PPM jack — you can drive both a digital receiver and a PPM trainer port simultaneously if your setup needs both.

Verify the chain

If your model uses a flight controller (iNav / Betaflight / Ardupilot), the receiver tab is the easiest way to sanity-check the chain. The FC config is the boring default:

iNav Receiver Mode panel — Receiver type SERIAL, Serial Receiver Provider SBUS, Serial Port Inverted OFF, Serial receiver half-duplex OFF — iNav Receiver Mode — typical SBUS config. Provider **SBUS**, Inverted **OFF**, Half-duplex **OFF**.

Don’t forget to assign the right UART to “Serial RX” in the Ports tab. After that, the Receiver tab fills in as soon as the radio link is healthy — bars per channel, AETR mapping, RSSI on the channel you’ve configured:

iNav Receiver tab — channel bars showing Roll/Pitch/Yaw/Throttle near centre, switch channels at their resting positions, RSSI channel CH14 — iNav Receiver tab with a healthy link — sticks near centre, switches at their resting positions, RSSI on the channel you've assigned. Move your sticks and the bars track.

If you don’t have a flight controller, the equivalent sanity-check is plugging the receiver into a servo and watching it move when you push the stick — same signal, different consumer.

Wiring

See External TX Modules for the stereo cable layout, the UART pad alternative, and power options — the same wiring patterns work for any digital protocol Magic Box outputs.

Flying FlySky gear? See IBUS.
Running an ExpressLRS or Crossfire TX module? See CRSF.
Want the analog path? See PPM.