diff --git a/src/decode/p25/P25Interleave.java b/src/decode/p25/P25Interleave.java
new file mode 100644
index 00000000..3bf069a5
--- /dev/null
+++ b/src/decode/p25/P25Interleave.java
@@ -0,0 +1,56 @@
+package decode.p25;
+
+import java.util.BitSet;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import bits.BitSetBuffer;
+
+/**
+ * Utility class to deinterleave P25 packet blocks of 196-bit length.
+ */
+public class P25Interleave
+{
+	private final static Logger mLog = 
+			LoggerFactory.getLogger( P25Interleave.class );
+
+	private static int[] MATRIX = new int[] { 0,1,2,3,16,17,18,19,32,33,34,35,
+			48,49,50,51,64,65,66,67,80,81,82,83,96,97,98,99,112,113,114,115,
+			128,129,130,131,144,145,146,147,160,161,162,163,176,177,178,179,
+			192,193,194,195,4,5,6,7,20,21,22,23,36,37,38,39,52,53,54,55,68,
+			69,70,71,84,85,86,87,100,101,102,103,116,117,118,119,132,133,
+			134,135,148,149,150,151,164,165,166,167,180,181,182,183,8,9,10,
+			11,24,25,26,27,40,41,42,43,56,57,58,59,72,73,74,75,88,89,90,91,
+			104,105,106,107,120,121,122,123,136,137,138,139,152,153,154,155,
+			168,169,170,171,184,185,186,187,12,13,14,15,28,29,30,31,44,45,
+			46,47,60,61,62,63,76,77,78,79,92,93,94,95,108,109,110,111,124,
+			125,126,127,140,141,142,143,156,157,158,159,172,173,174,175,188,
+			189,190,191 };
+
+	/**
+	 * Deinterleaves the 196-bit block in message, identified by start and end
+	 * bit positions.  Note: end index (exclusive) should be one more than the 
+	 * last bit in the block.
+	 * 
+	 * @param message - source message to deinterleave
+	 * @param start - starting bit index for the block
+	 * @param end - ending bit index for the block, plus 1
+	 */
+	public static void deinterleave( BitSetBuffer message, int start, int end )
+	{
+		BitSet original = message.get( start, end );
+
+		/* Clear block bits in source message */
+		message.clear( start, end );
+
+		/* Iterate only the set bits in the original message and apply 
+		 * the deinterleave -- we don't have to evaluate the 0 bits */
+		for (int i = original.nextSetBit( 0 ); 
+				 i >= 0 && i < MATRIX.length; 
+				 i = message.nextSetBit( i + 1 ) ) 
+		{
+			message.set( start + MATRIX[ i ] );
+		}
+	}
+}