diff --git a/apps/px4io/dsm.c b/apps/px4io/dsm.c
index 560ef47d94..869c27b1b5 100644
--- a/apps/px4io/dsm.c
+++ b/apps/px4io/dsm.c
@@ -241,6 +241,7 @@ dsm_guess_format(bool reset)
 		0x3f,	/* 6 channels (DX6) */
 		0x7f,	/* 7 channels (DX7) */
 		0xff,	/* 8 channels (DX8) */
+		0x1ff,	/* 9 channels (DX9, etc.) */
 		0x3ff,	/* 10 channels (DX10) */
 		0x3fff	/* 18 channels (DX10) */
 	};