diff --git a/src/prot.cpp b/src/prot.cpp
index ca1e397..e242690 100755
--- a/src/prot.cpp
+++ b/src/prot.cpp
@@ -368,6 +368,9 @@ uint8_t recBuffer[FRAME_MAXLEN];
     // read from "VCP":
     mySerialPort->readFromSerial(Indata, recLength);
 //qDebug()<<"prot: got data " << recLength;
+
+    memset(recBuffer, 0x00, sizeof(recBuffer));
+
     if (recLength>FRAME_MAXLEN)
         recLength=FRAME_MAXLEN;
     for (int nn=0; nn<recLength; nn++)