diff --git a/src/main/java/teetime/framework/signal/StartingSignal.java b/src/main/java/teetime/framework/signal/StartingSignal.java
index f8e001592ba6250696beef8201c61fd8c64307da..38ad2ce4d4011c0f36adfe7ee583e1fd3932f324 100644
--- a/src/main/java/teetime/framework/signal/StartingSignal.java
+++ b/src/main/java/teetime/framework/signal/StartingSignal.java
@@ -30,7 +30,7 @@ public final class StartingSignal implements ISignal {
 
 	@Override
 	public boolean mayBeTriggered(final Set<InputPort<?>> receivedInputPorts, final List<InputPort<?>> allInputPorts) {
-		return true;
+		return receivedInputPorts.size() == 1;
 	}
 
 }