diff --git a/src/rig.c b/src/rig.c
index 0463cb7b5..20745be59 100644
--- a/src/rig.c
+++ b/src/rig.c
@@ -4053,7 +4053,7 @@ int HAMLIB_API rig_set_split_mode(RIG *rig,
         RETURNFUNC(RIG_OK);
     }
 
-    if (tx_vfo & (RIG_VFO_CURR || RIG_VFO_TX))
+    if (tx_vfo & (RIG_VFO_CURR | RIG_VFO_TX))
     {
         rig_debug(RIG_DEBUG_WARN, "%s(%d): Unhandled TXVFO=%s, tx_mode=%s\n", __func__,
               __LINE__, rig_strvfo(tx_vfo), rig_strrmode(tx_mode));