diff --git a/TBF/Rig/TestMethods/iPerlCommunication/iPerlHead/IperlHead.cs b/TBF/Rig/TestMethods/iPerlCommunication/iPerlHead/IperlHead.cs
index 99fab1f46..9175a741c 100644
--- a/TBF/Rig/TestMethods/iPerlCommunication/iPerlHead/IperlHead.cs
+++ b/TBF/Rig/TestMethods/iPerlCommunication/iPerlHead/IperlHead.cs
@@ -444,7 +444,11 @@ namespace TBF.Rig.TestMethods.iPerlCommunication.iPerlHead
 			Q2ErrWOCorrection = 0;
 			Q2CorrRL = 0;
             Q2CorrLR = 0;
-			
+
+            if (optoSerialPort != null && optoSerialPort.IsOpen)
+            {
+                optoSerialPort.DiscardInBuffer();
+            }
             StartDataStreamProcessing();
 
             currentFlowDir = InitFlowDir;