diff --git a/p25/DataPacket.cpp b/p25/DataPacket.cpp
index cd4166fe..0ef94454 100644
--- a/p25/DataPacket.cpp
+++ b/p25/DataPacket.cpp
@@ -302,6 +302,17 @@ bool DataPacket::process(uint8_t* data, uint32_t len)
                     }
                 }
                 break;
+                case PDU_SAP_TRUNK_CTRL:
+                {
+                    for (uint32_t i = 0; i < blocksToFollow; i++) {
+                        uint8_t data[P25_TSBK_FEC_LENGTH_BYTES + 2U];
+                        ::memset(data, 0x00U, P25_TSBK_FEC_LENGTH_BYTES + 2U);
+
+                        uint32_t len = m_rfData[i].getData(data + 2U);
+                        m_p25->m_trunk->process(data, len, true);
+                    }
+                }
+                break;
                 default:
                     ::ActivityLog("P25", true, "RF data transmission from %u to %u, %u blocks", m_rfDataHeader.getLLId(), m_rfDataHeader.getLLId(), m_rfDataHeader.getBlocksToFollow());
 
diff --git a/p25/P25Defines.h b/p25/P25Defines.h
index 766353ce..4225c6a9 100644
--- a/p25/P25Defines.h
+++ b/p25/P25Defines.h
@@ -210,6 +210,7 @@ namespace p25
     const uint8_t   PDU_FMT_RSP = 0x03U;
     const uint8_t   PDU_FMT_UNCONFIRMED = 0x15U;
     const uint8_t   PDU_FMT_CONFIRMED = 0x16U;
+    const uint8_t   PDU_FMT_AMBT = 0x17U;
 
     // PDU SAP 
     const uint8_t   PDU_SAP_USER_DATA = 0x00U;
@@ -221,6 +222,7 @@ namespace p25
     const uint8_t   PDU_SAP_REG = 0x20U;
     const uint8_t   PDU_SAP_UNENC_KMM = 0x28U;
     const uint8_t   PDU_SAP_ENC_KMM = 0x29U;
+    const uint8_t   PDU_SAP_TRUNK_CTRL = 0x3DU;
 
     // PDU ACK Class
     const uint8_t   PDU_ACK_CLASS_ACK = 0x00U;
diff --git a/p25/TrunkPacket.cpp b/p25/TrunkPacket.cpp
index f76d5179..36af0dab 100644
--- a/p25/TrunkPacket.cpp
+++ b/p25/TrunkPacket.cpp
@@ -157,23 +157,30 @@ void TrunkPacket::resetNet()
 /// </summary>
 /// <param name="data">Buffer containing data frame.</param>
 /// <param name="len">Length of data frame.</param>
+/// <param name="mbtData">Flag indicating the data parameter contains MBT data.</param>
 /// <returns></returns>
-bool TrunkPacket::process(uint8_t* data, uint32_t len)
+bool TrunkPacket::process(uint8_t* data, uint32_t len, bool mbtData)
 {
     assert(data != NULL);
 
     if (!m_p25->m_control)
         return false;
 
-    // Decode the NID
-    bool valid = m_p25->m_nid.decode(data + 2U);
+    uint8_t duid = 0U;
+    if (!mbtData) {
+        // Decode the NID
+        bool valid = m_p25->m_nid.decode(data + 2U);
 
-    if (m_p25->m_rfState == RS_RF_LISTENING && !valid)
-        return false;
+        if (m_p25->m_rfState == RS_RF_LISTENING && !valid)
+            return false;
 
-    RPT_RF_STATE prevRfState = m_p25->m_rfState;
-    uint8_t duid = m_p25->m_nid.getDUID();
+        duid = m_p25->m_nid.getDUID();
+    } else {
+        duid = P25_DUID_TSDU;
+    }
 
+    RPT_RF_STATE prevRfState = m_p25->m_rfState;
+    
     // handle individual DUIDs
     if (duid == P25_DUID_TSDU) {
         if (m_p25->m_rfState != RS_RF_DATA) {
diff --git a/p25/TrunkPacket.h b/p25/TrunkPacket.h
index aa8ac381..7bbb31e7 100644
--- a/p25/TrunkPacket.h
+++ b/p25/TrunkPacket.h
@@ -61,7 +61,7 @@ namespace p25
         void resetNet();
 
         /// <summary>Process a data frame from the RF interface.</summary>
-        bool process(uint8_t* data, uint32_t len);
+        bool process(uint8_t* data, uint32_t len, bool mbtData = false);
         /// <summary>Process a data frame from the network.</summary>
         bool processNetwork(uint8_t* data, uint32_t len, lc::LC& control, data::LowSpeedData& lsd, uint8_t& duid);
 
diff --git a/p25/data/DataHeader.cpp b/p25/data/DataHeader.cpp
index e111210d..30e13d4a 100644
--- a/p25/data/DataHeader.cpp
+++ b/p25/data/DataHeader.cpp
@@ -54,6 +54,7 @@ DataHeader::DataHeader() :
     m_n(0U),
     m_seqNo(0U),
     m_headerOffset(0U),
+    m_ambtOpcode(0U),
     m_trellis(),
     m_blocksToFollow(0U),
     m_padCount(0U),
@@ -103,8 +104,15 @@ bool DataHeader::decode(const uint8_t* data)
     m_llId = (header[3U] << 16) + (header[4U] << 8) + header[5U];               // Logical Link ID
 
     m_fullMessage = (header[6U] & 0x80U) == 0x80U;                              // Full Message Flag
+
     m_blocksToFollow = header[6U] & 0x7FU;                                      // Block Frames to Follow
-    m_padCount = header[7U] & 0x1FU;                                            // Pad Count
+    if (m_fmt == PDU_FMT_AMBT) {
+        m_padCount = 0;
+        m_ambtOpcode = header[7U] & 0x3FU;                                      // AMBT Opcode
+    }
+    else {
+        m_padCount = header[7U] & 0x1FU;                                        // Pad Count
+    }
 
     if (m_fmt == PDU_FMT_CONFIRMED) {
         m_dataOctets = 16 * m_blocksToFollow - 4 - m_padCount;
@@ -150,7 +158,12 @@ void DataHeader::encode(uint8_t* data)
     header[6U] = (m_fullMessage ? 0x80U : 0x00U) +                              // Full Message Flag
         (m_blocksToFollow & 0x7FU);                                             // Blocks Frames to Follow
 
-    header[7U] = (m_padCount & 0x1FU);                                          // Pad Count
+    if (m_fmt == PDU_FMT_AMBT) {
+        header[7U] = (m_ambtOpcode & 0x3FU);                                    // AMBT Opcode
+    }
+    else {
+        header[7U] = (m_padCount & 0x1FU);                                      // Pad Count
+    }
 
     header[8U] = (m_sync ? 0x80U : 0x00U) +                                     // Re-synchronize Flag
         ((m_n << 4) && 0x07U) +                                                 // Packet Sequence No.
@@ -191,6 +204,7 @@ void DataHeader::reset()
     m_seqNo = 0U;
 
     m_headerOffset = 0U;
+    m_ambtOpcode = 0U;
 }
 
 /// <summary>Gets the total number of data octets.</summary>
diff --git a/p25/data/DataHeader.h b/p25/data/DataHeader.h
index 57f5a231..084e94bf 100644
--- a/p25/data/DataHeader.h
+++ b/p25/data/DataHeader.h
@@ -91,6 +91,8 @@ namespace p25
             __PROPERTY(uint8_t, seqNo, SeqNo);
             /// <summary>Offset of the header.</summary>
             __PROPERTY(uint8_t, headerOffset, HeaderOffset);
+            /// <summary>Alternate Trunking Block Opcode</summary>
+            __PROPERTY(uint8_t, ambtOpcode, AMBTOpcode);
 
         private:
             edac::Trellis m_trellis;