diff --git a/src/module/decode/p25/message/tsbk/TSBKMessageFactory.java b/src/module/decode/p25/message/tsbk/TSBKMessageFactory.java
index e06ac784..3e8ab315 100644
--- a/src/module/decode/p25/message/tsbk/TSBKMessageFactory.java
+++ b/src/module/decode/p25/message/tsbk/TSBKMessageFactory.java
@@ -1,5 +1,7 @@
 package module.decode.p25.message.tsbk;
 
+import alias.AliasList;
+import bits.BinaryMessage;
 import module.decode.p25.message.tsbk.motorola.ControlChannelBaseStationIdentification;
 import module.decode.p25.message.tsbk.motorola.MotorolaOpcode;
 import module.decode.p25.message.tsbk.motorola.MotorolaTSBKMessage;
@@ -19,6 +21,7 @@ import module.decode.p25.message.tsbk.osp.control.ExtendedFunctionCommand;
 import module.decode.p25.message.tsbk.osp.control.GroupAffiliationQuery;
 import module.decode.p25.message.tsbk.osp.control.GroupAffiliationResponse;
 import module.decode.p25.message.tsbk.osp.control.IdentifierUpdateNonVUHF;
+import module.decode.p25.message.tsbk.osp.control.IdentifierUpdateTDMA;
 import module.decode.p25.message.tsbk.osp.control.IdentifierUpdateVUHF;
 import module.decode.p25.message.tsbk.osp.control.LocationRegistrationResponse;
 import module.decode.p25.message.tsbk.osp.control.MessageUpdate;
@@ -56,8 +59,6 @@ import module.decode.p25.message.tsbk.osp.voice.UnitToUnitVoiceChannelGrantUpdat
 import module.decode.p25.reference.DataUnitID;
 import module.decode.p25.reference.Opcode;
 import module.decode.p25.reference.Vendor;
-import alias.AliasList;
-import bits.BinaryMessage;
 
 public class TSBKMessageFactory
 {
@@ -119,6 +120,8 @@ public class TSBKMessageFactory
                     case IDENTIFIER_UPDATE_NON_VUHF:
                         return new IdentifierUpdateNonVUHF( message, duid, 
                         		aliasList );
+                    case IDENTIFIER_UPDATE_TDMA:
+                    	return new IdentifierUpdateTDMA( message, duid, aliasList );
                     case IDENTIFIER_UPDATE_VHF_UHF_BANDS:
                         return new IdentifierUpdateVUHF( message, duid, 
                         		aliasList );
diff --git a/src/module/decode/p25/message/tsbk/osp/control/IdentifierUpdateTDMA.java b/src/module/decode/p25/message/tsbk/osp/control/IdentifierUpdateTDMA.java
new file mode 100644
index 00000000..e2189ef0
--- /dev/null
+++ b/src/module/decode/p25/message/tsbk/osp/control/IdentifierUpdateTDMA.java
@@ -0,0 +1,153 @@
+package module.decode.p25.message.tsbk.osp.control;
+
+import module.decode.p25.reference.DataUnitID;
+import module.decode.p25.reference.Opcode;
+import alias.AliasList;
+import bits.BinaryMessage;
+
+public class IdentifierUpdateTDMA extends IdentifierUpdate
+{
+    public static final int[] CHANNEL_TYPE = { 84,85,86,87 };
+    public static final int TRANSMIT_OFFSET_SIGN = 88;
+    public static final int[] TRANSMIT_OFFSET = { 89,90,91,92,93,94,95,96,97,98,
+    	99,100,101 };
+    
+    public IdentifierUpdateTDMA( BinaryMessage message, 
+                             DataUnitID duid,
+                             AliasList aliasList ) 
+    {
+        super( message, duid, aliasList );
+    }
+    
+    @Override
+    public String getEventType()
+    {
+    	return Opcode.IDENTIFIER_UPDATE_TDMA.getDescription();
+    }
+    
+    public String getMessage()
+    {
+        StringBuilder sb = new StringBuilder();
+        
+        sb.append( getMessageStub() );
+
+        sb.append( " IDEN:" + getIdentifier() );
+        sb.append( " BASE:" + getBaseFrequency() );
+        sb.append( " BW:" + getBandwidth() );
+        sb.append( " SPACING:" + getChannelSpacing() );
+        sb.append( " OFFSET:" + getTransmitOffset() );
+        sb.append( " TYPE:" + getChannelType().toString() );
+        
+        return sb.toString();
+    }
+    
+    public ChannelType getChannelType()
+    {
+    	return ChannelType.fromValue( mMessage.getInt( CHANNEL_TYPE) );
+    }
+
+    /**
+     * Channel bandwidth in hertz
+     */
+    public int getBandwidth()
+    {
+    	return getChannelType().getBandwidth();
+    }
+
+    /**
+     * Transmit offset in hertz
+     */
+    @Override
+    public long getTransmitOffset()
+    {
+        long offset = mMessage.getLong( TRANSMIT_OFFSET ) * 
+        		getChannelSpacing();
+        
+        if( mMessage.get( TRANSMIT_OFFSET_SIGN ) )
+        {
+            return offset;
+        }
+        else
+        {
+            return -offset;
+        }
+    }
+    
+    public enum ChannelType
+    {
+    	TYPE_0( AccessType.FDMA, 12500, 1, Vocoder.HALF_RATE ),
+    	TYPE_1( AccessType.FDMA, 12500, 1, Vocoder.FULL_RATE ),
+    	TYPE_2( AccessType.FDMA,  6250, 1, Vocoder.HALF_RATE ),
+    	TYPE_3( AccessType.TDMA, 12500, 2, Vocoder.HALF_RATE ),
+    	TYPE_4( AccessType.TDMA, 25000, 4, Vocoder.HALF_RATE ),
+    	TYPE_5( AccessType.TDMA, 12500, 2, Vocoder.HALF_RATE ), //HD8PSK simulcast
+    	UNKNOWN( AccessType.UNKNOWN, 0, 0, Vocoder.HALF_RATE );
+    	
+    	private AccessType mAccessType;
+    	private int mBandwidth;
+    	private int mSlotsPerCarrier;
+    	private Vocoder mVocoder;
+
+    	private ChannelType( AccessType accessType, 
+    						 int bandwidth, 
+    						 int slots,
+    						 Vocoder vocoder )
+    	{
+    		mAccessType = accessType;
+    		mBandwidth = bandwidth;
+    		mSlotsPerCarrier = slots;
+    		mVocoder = vocoder;
+    	}
+    	
+    	public String toString()
+    	{
+    		StringBuilder sb = new StringBuilder();
+    		sb.append( mAccessType.name() );
+    		sb.append( " BW:" + mBandwidth );
+    		sb.append( " SLOT/CARRIER:" + mSlotsPerCarrier );
+    		sb.append( " VOCODER:" + mVocoder.name() );
+    		
+    		return sb.toString();
+    	}
+    	
+    	public static ChannelType fromValue( int value )
+    	{
+    		if( 0 <= value && value <= 5 )
+    		{
+    			return ChannelType.values()[ value ];
+    		}
+    		
+    		return ChannelType.UNKNOWN;
+    	}
+    	
+    	public AccessType getAccessType()
+    	{
+    		return mAccessType;
+    	}
+    	
+    	public int getBandwidth()
+    	{
+    		return mBandwidth;
+    	}
+    	
+    	public int getSlotsPerCarrier()
+    	{
+    		return mSlotsPerCarrier;
+    	}
+    	
+    	public Vocoder getVocoder()
+    	{
+    		return mVocoder;
+    	}
+    }
+    
+    public enum AccessType
+    {
+    	FDMA,TDMA,UNKNOWN;
+    }
+    
+    public enum Vocoder
+    {
+    	HALF_RATE, FULL_RATE;
+    }
+}
diff --git a/src/module/decode/p25/reference/Opcode.java b/src/module/decode/p25/reference/Opcode.java
index 4dbf8870..d94afec8 100644
--- a/src/module/decode/p25/reference/Opcode.java
+++ b/src/module/decode/p25/reference/Opcode.java
@@ -53,7 +53,7 @@ public enum Opcode
 	TDMA_SYNC_BROADCAST( "TDMA_SYNC_BCST  ", "FDMA-TDMA Sync Broadcast", 48 ),
 	RESERVED_31( "RESERVED_31     ", "Reserved", 49 ),
 	RESERVED_32( "RESERVED_32     ", "Reserved", 50 ),
-	RESERVED_33( "RESERVED_33     ", "Reserved", 51 ),
+	IDENTIFIER_UPDATE_TDMA( "IDEN_UPDATE_TDMA", "Identifier Update for TDMA", 51 ),
 	IDENTIFIER_UPDATE_VHF_UHF_BANDS( "IDEN_UPDATE_VUHF", "Identifier Update for VHF/UHF Bands", 52 ),
 	TIME_DATE_ANNOUNCEMENT( "TIME_DATE_ANNOUN", "Time and Date Announcement", 53 ),
 	ROAMING_ADDRESS_COMMAND( "ROAM_ADDR_CMD   ", "Roaming Address Command", 54 ),