diff --git a/p25/dfsi/packet/DFSITrunk.cpp b/p25/dfsi/packet/DFSITrunk.cpp
index 049f78ec..efa84341 100644
--- a/p25/dfsi/packet/DFSITrunk.cpp
+++ b/p25/dfsi/packet/DFSITrunk.cpp
@@ -198,6 +198,18 @@ void DFSITrunk::writeRF_TSDU_SBF(bool noNetwork, bool clearBeforeWrite, bool for
     writeRF_DSFI_Stop(P25_DFSI_TYPE_TSBK);
 }
 
+/// <summary>
+/// Helper to write a alternate multi-block trunking PDU packet.
+/// </summary>
+/// <param name="clearBeforeWrite"></param>
+void DFSITrunk::writeRF_TSDU_AMBT(bool clearBeforeWrite)
+{
+    if (!m_p25->m_control)
+        return;
+
+    // for now this is ignored...
+}
+
 /// <summary>
 /// Helper to write a network single-block P25 TSDU packet.
 /// </summary>
diff --git a/p25/dfsi/packet/DFSITrunk.h b/p25/dfsi/packet/DFSITrunk.h
index 11d3031d..195ebb83 100644
--- a/p25/dfsi/packet/DFSITrunk.h
+++ b/p25/dfsi/packet/DFSITrunk.h
@@ -74,6 +74,8 @@ namespace p25
 
                 /// <summary>Helper to write a single-block P25 TSDU packet.</summary>
                 virtual void writeRF_TSDU_SBF(bool noNetwork, bool clearBeforeWrite = false, bool force = false);
+                /// <summary>Helper to write a alternate multi-block trunking PDU packet.</summary>
+                virtual void writeRF_TSDU_AMBT(bool clearBeforeWrite = false);
 
                 /// <summary>Helper to write a network P25 TDU w/ link control packet.</summary>
                 //virtual void writeNet_TDULC(lc::TDULC lc);
diff --git a/p25/packet/Data.cpp b/p25/packet/Data.cpp
index 666007ca..ddbf5075 100644
--- a/p25/packet/Data.cpp
+++ b/p25/packet/Data.cpp
@@ -505,6 +505,52 @@ bool Data::hasLLIdFNEReg(uint32_t llId) const
     }
 }
 
+/// <summary>
+/// Helper to write user data as a P25 PDU packet.
+/// </summary>
+/// <param name="dataHeader"></param>
+/// <param name="pduUserData"></param>
+/// <param name="clearBeforeWrite"></param>
+void Data::writeRF_PDU_User(data::DataHeader dataHeader, const uint8_t* pduUserData, bool clearBeforeWrite)
+{
+    assert(pduUserData != NULL);
+
+    uint32_t bitLength = ((dataHeader.getBlocksToFollow() + 1U) * P25_PDU_FEC_LENGTH_BITS) + P25_PREAMBLE_LENGTH_BITS;
+    uint32_t offset = P25_PREAMBLE_LENGTH_BITS;
+
+    uint8_t data[bitLength / 8U];
+    ::memset(data, 0x00U, bitLength / 8U);
+    uint8_t block[P25_PDU_FEC_LENGTH_BYTES];
+    ::memset(block, 0x00U, P25_PDU_FEC_LENGTH_BYTES);
+
+    // Generate the PDU header and 1/2 rate Trellis
+    dataHeader.encode(block);
+    Utils::setBitRange(block, data, offset, P25_PDU_FEC_LENGTH_BITS);
+    offset += P25_PDU_FEC_LENGTH_BITS;
+
+    // Generate the PDU data
+    DataBlock rspBlock = DataBlock();
+    uint32_t dataOffset = 0U;
+    for (uint8_t i = 0; i < dataHeader.getBlocksToFollow(); i++) {
+        rspBlock.setFormat(PDU_FMT_UNCONFIRMED);
+        rspBlock.setSerialNo(0U);
+        rspBlock.setData(pduUserData + dataOffset);
+
+        ::memset(block, 0x00U, P25_PDU_FEC_LENGTH_BYTES);
+        rspBlock.encode(block);
+        Utils::setBitRange(block, data, offset, P25_PDU_FEC_LENGTH_BITS);
+        offset += P25_PDU_FEC_LENGTH_BITS;
+        dataOffset += P25_PDU_UNCONFIRMED_LENGTH_BYTES;
+    }
+
+    if (clearBeforeWrite) {
+        m_p25->m_modem->clearP25Data();
+        m_p25->m_queue.clear();
+    }
+
+    writeRF_PDU(data, bitLength);
+}
+
 /// <summary>
 /// Updates the processor by the passed number of milliseconds.
 /// </summary>
diff --git a/p25/packet/Data.h b/p25/packet/Data.h
index d959b595..4bdfeeb6 100644
--- a/p25/packet/Data.h
+++ b/p25/packet/Data.h
@@ -73,13 +73,15 @@ namespace p25
             /// <summary>Helper to check if a logical link ID has registered with data services.</summary>
             bool hasLLIdFNEReg(uint32_t llId) const;
 
+            /// <summary>Helper to write user data as a P25 PDU packet.</summary>
+            void writeRF_PDU_User(data::DataHeader dataHeader, const uint8_t* pduUserData, bool clearBeforeWrite = false);
+
             /// <summary>Updates the processor by the passed number of milliseconds.</summary>
             void clock(uint32_t ms);
 
         private:
             friend class p25::Control;
             Control* m_p25;
-            friend class p25::packet::Trunk;
 
             network::BaseNetwork* m_network;
 
diff --git a/p25/packet/Trunk.cpp b/p25/packet/Trunk.cpp
index 546ab374..9ca8c35c 100644
--- a/p25/packet/Trunk.cpp
+++ b/p25/packet/Trunk.cpp
@@ -1670,61 +1670,32 @@ void Trunk::writeRF_TSDU_MBF(bool clearBeforeWrite)
 /// Helper to write a alternate multi-block trunking PDU packet.
 /// </summary>
 /// <param name="clearBeforeWrite"></param>
-void Trunk::writeRF_PDU_AMBT(bool clearBeforeWrite)
+void Trunk::writeRF_TSDU_AMBT(bool clearBeforeWrite)
 {
     if (!m_p25->m_control)
         return;
 
-    DataHeader rspHeader = DataHeader();
-    uint8_t rspData[P25_PDU_UNCONFIRMED_LENGTH_BYTES * P25_MAX_PDU_COUNT];
-    ::memset(rspData, 0x00U, P25_PDU_UNCONFIRMED_LENGTH_BYTES * P25_MAX_PDU_COUNT);
+    DataHeader header = DataHeader();
+    uint8_t pduUserData[P25_PDU_UNCONFIRMED_LENGTH_BYTES * P25_MAX_PDU_COUNT];
+    ::memset(pduUserData, 0x00U, P25_PDU_UNCONFIRMED_LENGTH_BYTES * P25_MAX_PDU_COUNT);
 
     // Generate TSBK block
     m_rfTSBK.setLastBlock(true); // always set last block -- this a Single Block TSDU
-    m_rfTSBK.encodeMBT(rspHeader, rspData);
+    m_rfTSBK.encodeMBT(header, pduUserData);
 
     if (m_debug) {
+        LogDebug(LOG_RF, P25_PDU_STR ", ack = %u, outbound = %u, fmt = $%02X, sap = $%02X, fullMessage = %u, blocksToFollow = %u, padCount = %u, n = %u, seqNo = %u, hdrOffset = %u",
+            header.getAckNeeded(), header.getOutbound(), header.getFormat(), header.getSAP(), header.getFullMessage(),
+            header.getBlocksToFollow(), header.getPadCount(), header.getNs(), header.getFSN(),
+            header.getHeaderOffset());
         LogDebug(LOG_RF, P25_PDU_STR " AMBT, lco = $%02X, mfId = $%02X, lastBlock = %u, AIV = %u, EX = %u, srcId = %u, dstId = %u, sysId = $%03X, netId = $%05X",
             m_rfTSBK.getLCO(), m_rfTSBK.getMFId(), m_rfTSBK.getLastBlock(), m_rfTSBK.getAIV(), m_rfTSBK.getEX(), m_rfTSBK.getSrcId(), m_rfTSBK.getDstId(),
             m_rfTSBK.getSysId(), m_rfTSBK.getNetId());
 
-        Utils::dump(1U, "!!! *TSDU (AMBT) TSBK Block Data", rspData, P25_PDU_UNCONFIRMED_LENGTH_BYTES * rspHeader.getBlocksToFollow());
+        Utils::dump(1U, "!!! *PDU (AMBT) TSBK Block Data", pduUserData, P25_PDU_UNCONFIRMED_LENGTH_BYTES * header.getBlocksToFollow());
     }
 
-    uint32_t bitLength = ((rspHeader.getBlocksToFollow() + 1U) * P25_PDU_FEC_LENGTH_BITS) + P25_PREAMBLE_LENGTH_BITS;
-    uint32_t offset = P25_PREAMBLE_LENGTH_BITS;
-
-    uint8_t data[bitLength / 8U];
-    ::memset(data, 0x00U, bitLength / 8U);
-    uint8_t block[P25_PDU_FEC_LENGTH_BYTES];
-    ::memset(block, 0x00U, P25_PDU_FEC_LENGTH_BYTES);
-
-    // Generate the PDU header and 1/2 rate Trellis
-    rspHeader.encode(block);
-    Utils::setBitRange(block, data, offset, P25_PDU_FEC_LENGTH_BITS);
-    offset += P25_PDU_FEC_LENGTH_BITS;
-
-    // Generate the PDU data
-    DataBlock rspBlock = DataBlock();
-    uint32_t dataOffset = 0U;
-    for (uint8_t i = 0; i < rspHeader.getBlocksToFollow(); i++) {
-        rspBlock.setFormat(PDU_FMT_UNCONFIRMED);
-        rspBlock.setSerialNo(0U);
-        rspBlock.setData(rspData + dataOffset);
-
-        ::memset(block, 0x00U, P25_PDU_FEC_LENGTH_BYTES);
-        rspBlock.encode(block);
-        Utils::setBitRange(block, data, offset, P25_PDU_FEC_LENGTH_BITS);
-        offset += P25_PDU_FEC_LENGTH_BITS;
-        dataOffset += P25_PDU_UNCONFIRMED_LENGTH_BYTES;
-    }
-
-    if (clearBeforeWrite) {
-        m_p25->m_modem->clearP25Data();
-        m_p25->m_queue.clear();
-    }
-
-    m_p25->m_data->writeRF_PDU(data, bitLength);
+    m_p25->m_data->writeRF_PDU_User(header, pduUserData, clearBeforeWrite);
 }
 
 /// <summary>
diff --git a/p25/packet/Trunk.h b/p25/packet/Trunk.h
index 31498fe3..bb12fea3 100644
--- a/p25/packet/Trunk.h
+++ b/p25/packet/Trunk.h
@@ -83,6 +83,7 @@ namespace p25
 
             /// <summary>Helper to set the TSBK manufacturer ID.</summary>
             void setMFId(uint8_t val) { m_rfTSBK.setMFId(val); }
+
             /// <summary>Helper to write a call alert packet.</summary>
             void writeRF_TSDU_Call_Alrt(uint32_t srcId, uint32_t dstId);
             /// <summary>Helper to write a call alert packet.</summary>
@@ -179,7 +180,7 @@ namespace p25
             /// <summary>Helper to write a multi-block (3-block) P25 TSDU packet.</summary>
             void writeRF_TSDU_MBF(bool clearBeforeWrite = false);
             /// <summary>Helper to write a alternate multi-block trunking PDU packet.</summary>
-            void writeRF_PDU_AMBT(bool clearBeforeWrite = false);
+            virtual void writeRF_TSDU_AMBT(bool clearBeforeWrite = false);
 
             /// <summary>Helper to generate the given control TSBK into the TSDU frame queue.</summary>
             void queueRF_TSBK_Ctrl(uint8_t lco);