diff --git a/Common/DStarDefines.h b/Common/DStarDefines.h
index 6d1319e..b0c3972 100644
--- a/Common/DStarDefines.h
+++ b/Common/DStarDefines.h
@@ -111,10 +111,6 @@ const unsigned int  DSTAR_FRAMES_PER_SEC = 50U;
 const unsigned char SCRAMBLER_BYTE1 = 0x70U;
 const unsigned char SCRAMBLER_BYTE2 = 0x4FU;
 const unsigned char SCRAMBLER_BYTE3 = 0x93U;
-const unsigned char SCRAMBLER_BYTE4 = 0x40U;
-const unsigned char SCRAMBLER_BYTE5 = 0x64U;
-
-const unsigned char FAST_DATA_GUARD_BYTE = 0x02U;
 
 const unsigned int  DPLUS_PORT  = 20001U;
 const unsigned int  DEXTRA_PORT = 30001U;
diff --git a/Common/RepeaterHandler.cpp b/Common/RepeaterHandler.cpp
index e2953a6..6f883fb 100644
--- a/Common/RepeaterHandler.cpp
+++ b/Common/RepeaterHandler.cpp
@@ -743,8 +743,7 @@ void CRepeaterHandler::processRepeater(CAMBEData& data)
 	// Check for the fast data signature
 	if (!m_fastData) {
 		unsigned char slowDataType = (buffer[VOICE_FRAME_LENGTH_BYTES] ^ SCRAMBLER_BYTE1) & SLOW_DATA_TYPE_MASK;
-		unsigned char guard = buffer[4U] ^ SCRAMBLER_BYTE5;
-		if ((slowDataType == SLOW_DATA_TYPE_FAST_DATA1 || slowDataType == SLOW_DATA_TYPE_FAST_DATA2) /* && guard == FAST_DATA_GUARD_BYTE */)
+		if (slowDataType == SLOW_DATA_TYPE_FAST_DATA1 || slowDataType == SLOW_DATA_TYPE_FAST_DATA2)
 			m_fastData = true;
 	}