diff --git a/src/main/java/cit/PureATN/DPenReceiver.java b/src/main/java/cit/PureATN/DPenReceiver.java
index 2b6f46d..68fed4e 100644
--- a/src/main/java/cit/PureATN/DPenReceiver.java
+++ b/src/main/java/cit/PureATN/DPenReceiver.java
@@ -19,7 +19,8 @@
 
     public DPenReceiver(Note _note){
         note = _note;
-
+		initPenHash();
+		
         serverThread = new Thread(this);
 		serverThread.start();