diff --git a/src/modules/px4iofirmware/protocol.h b/src/modules/px4iofirmware/protocol.h
index 2ca5eb6492..d4b849c050 100644
--- a/src/modules/px4iofirmware/protocol.h
+++ b/src/modules/px4iofirmware/protocol.h
@@ -240,7 +240,7 @@ enum {							/* DSM bind states */
 
 #define PX4IO_P_SETUP_AIRMODE 			27 	/* air-mode */
 
-#define PX4IO_P_SETUP_ENABLE_FLIGHTTERMINATION	28	/* flight termination circuit breaker */
+#define PX4IO_P_SETUP_ENABLE_FLIGHTTERMINATION	28	/**< flight termination; false if the circuit breaker (CBRK_FLIGHTTERM) is set */
 
 #define PX4IO_THERMAL_IGNORE			UINT16_MAX
 #define PX4IO_THERMAL_OFF			0