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XM203 B.O.S.S. · Installation

FCU wiring options.

Wiring references for common fire control units (FCUs), showing where to take the positive, negative and trigger signal connections for the B.O.S.S. cable.

FCU 01

Perun V2

Perun V2 power connection points
1 & 2 = positive (red B.O.S.S. cable) · 3 = negative (black B.O.S.S. cable)
Perun V2 trigger signal solder points
The white trigger signal cable can be soldered to either of the two points shown.
Perun V2 cable connection
Completed cable connection.

Enable Start in Silent Mode. When a battery is connected, the Perun initialises the motor, which the XM203 can read as a shot. Update to the latest firmware and enable “Start in Silent Mode” so the unit is not live until you tap the up or down key.

Start in Silent Mode setting in RDX XComms Link

FCU 02

Spartan

This set-up uses the Invert Trigger option, currently in beta. Email boss@rdxtech.net to request access to the firmware. Thanks to rusty_mtw for the set-up instructions.

Why Invert Trigger?

The XM203 normally activates on a positive voltage. Some FCUs trigger the motor or solenoid by switching to ground, which leaves a constant positive voltage between shots and continuously activates the XM203. With Invert Trigger enabled, the XM203 activates only when no positive voltage is present.

When Invert Trigger is used, Start in Silent Mode is enabled automatically so the unit cannot fire on start-up before a positive voltage is detected.

Spartan FCU wiring example
Invert Trigger setting in RDX XComms Link

FCU 03

Polarstar

The header is not normally used, but pin #2 provides a signal in semi mode on Rev 3.0.0 FCU firmware. With FCU firmware 3.0.4, pin #2 also works in auto.

The matching wire harness is available from Polarstar. Thanks to Frederick and Real Team 6 (RT6).

Polarstar wire harness for the B.O.S.S. cable
Polarstar FCU wiring diagram for the B.O.S.S.

FCU 04

Leviathan

Thanks to AntTech and JeffTron.

Leviathan FCU B.O.S.S. wiring diagram 1
Leviathan FCU B.O.S.S. wiring diagram 2
Leviathan FCU B.O.S.S. wiring diagram 3