diff --git a/Common/DStarDefines.h b/Common/DStarDefines.h
index 6fbae59..cf5d356 100644
--- a/Common/DStarDefines.h
+++ b/Common/DStarDefines.h
@@ -58,10 +58,6 @@ const bool NULL_SLOW_DATA_BITS[] = {false, true,  true,  false, true,  false, fa
 									true,  false, false, true,  false, true,  false, false,
 									true,  false, true,  false, true,  true,  true,  true};
 
-const unsigned char KENWOOD_DATA_MODE_BYTES[] = {0xEEU, 0xC2U, 0xA1U, 0xC8U, 0x42U, 0x6EU, 0x52U, 0x51U, 0xC3U};
-const unsigned char ICOM_DATA_MODE_BYTES1[]   = {0xB2U, 0x4DU, 0x22U, 0x48U, 0xC0U, 0x16U, 0x28U, 0x26U, 0xC8U};
-const unsigned char ICOM_DATA_MODE_BYTES2[]   = {0x70U, 0x4FU, 0x93U, 0x40U, 0x64U, 0x74U, 0x6DU, 0x30U, 0x2BU};
-
 const unsigned int VOICE_FRAME_LENGTH_BITS   = 72U;
 const unsigned int VOICE_FRAME_LENGTH_BYTES  = VOICE_FRAME_LENGTH_BITS / 8U;
 
@@ -86,10 +82,14 @@ const unsigned int DATA_BLOCK_SIZE_BYTES = 21U * DV_FRAME_LENGTH_BYTES;
 const unsigned int LONG_CALLSIGN_LENGTH  = 8U;
 const unsigned int SHORT_CALLSIGN_LENGTH = 4U;
 
-const unsigned char SLOW_DATA_TYPE_MASK   = 0xF0U;
-const unsigned char SLOW_DATA_TYPE_GPS    = 0x30U;
-const unsigned char SLOW_DATA_TYPE_TEXT   = 0x40U;
-const unsigned char SLOW_DATA_TYPE_HEADER = 0x50U;
+const unsigned char SLOW_DATA_TYPE_MASK       = 0xF0U;
+const unsigned char SLOW_DATA_TYPE_GPS        = 0x30U;
+const unsigned char SLOW_DATA_TYPE_TEXT       = 0x40U;
+const unsigned char SLOW_DATA_TYPE_HEADER     = 0x50U;
+const unsigned char SLOW_DATA_TYPE_FAST_DATA1 = 0x80U;
+const unsigned char SLOW_DATA_TYPE_FAST_DATA2 = 0x90U;
+const unsigned char SLOW_DATA_TYPE_SQUELCH    = 0xC0U;
+const unsigned char SLOW_DATA_LENGTH_MASK     = 0x0FU;
 
 const unsigned char DATA_MASK           = 0x80U;
 const unsigned char REPEATER_MASK       = 0x40U;
diff --git a/Common/RepeaterHandler.cpp b/Common/RepeaterHandler.cpp
index 1a25db0..86d3cb2 100644
--- a/Common/RepeaterHandler.cpp
+++ b/Common/RepeaterHandler.cpp
@@ -740,13 +740,10 @@ void CRepeaterHandler::processRepeater(CAMBEData& data)
 	unsigned char buffer[DV_FRAME_MAX_LENGTH_BYTES];
 	data.getData(buffer, DV_FRAME_MAX_LENGTH_BYTES);
 
-	// Data signatures only appear at the beginning of the frame
-	if (!m_fastData && m_frames < 21U) {
-		if (::memcmp(buffer, KENWOOD_DATA_MODE_BYTES, VOICE_FRAME_LENGTH_BYTES) == 0)
-			m_fastData = true;
-		else if (::memcmp(buffer, ICOM_DATA_MODE_BYTES1, VOICE_FRAME_LENGTH_BYTES) == 0)
-			m_fastData = true;
-		else if (::memcmp(buffer, ICOM_DATA_MODE_BYTES2, VOICE_FRAME_LENGTH_BYTES) == 0)
+	// Check for the fast data signature
+	if (!m_fastData) {
+		unsigned char slowDataType = buffer[VOICE_FRAME_LENGTH_BYTES] & SLOW_DATA_TYPE_MASK;
+		if (slowDataType == SLOW_DATA_TYPE_FAST_DATA1 || slowDataType == SLOW_DATA_TYPE_FAST_DATA2)
 			m_fastData = true;
 	}