diff --git a/DMRSlot.cpp b/DMRSlot.cpp
index 124bdf15c..a26da2dd3 100644
--- a/DMRSlot.cpp
+++ b/DMRSlot.cpp
@@ -80,7 +80,7 @@ m_rfEmbeddedData(NULL),
 m_rfEmbeddedReadN(0U),
 m_rfEmbeddedWriteN(1U),
 m_rfTalkerId(TALKER_ID_NONE),
-m_rfTalkerAlias(NULL),
+m_rfTalkerAlias(),
 m_netEmbeddedLC(),
 m_netEmbeddedData(NULL),
 m_netEmbeddedReadN(0U),
@@ -117,8 +117,6 @@ m_aveRSSI(0U),
 m_rssiCount(0U),
 m_fp(NULL)
 {
-	m_rfTalkerAlias = new unsigned char[32U];
-
 	m_lastFrame = new unsigned char[DMR_FRAME_LENGTH_BYTES + 2U];
 
 	m_rfEmbeddedData  = new CDMREmbeddedData[2U];
@@ -132,7 +130,6 @@ CDMRSlot::~CDMRSlot()
 	delete[] m_rfEmbeddedData;
 	delete[] m_netEmbeddedData;
 	delete[] m_lastFrame;
-	delete[] m_rfTalkerAlias;
 }
 
 bool CDMRSlot::writeModem(unsigned char *data, unsigned int len)
@@ -632,9 +629,9 @@ bool CDMRSlot::writeModem(unsigned char *data, unsigned int len)
 
 					if (!(m_rfTalkerId & TALKER_ID_HEADER)) {
 						if (m_rfTalkerId == TALKER_ID_NONE)
-							::memset(m_rfTalkerAlias, '\0', 32U);
-						::memcpy(m_rfTalkerAlias, data, 6U);
-						m_display->writeDMRTA(m_slotNo, m_rfTalkerAlias, "R");
+							m_rfTalkerAlias.reset();
+						m_rfTalkerAlias.add(0, data, 7U);
+						m_display->writeDMRTA(m_slotNo, (unsigned char*)m_rfTalkerAlias.get(), "R");
 
 						if (m_dumpTAData) {
 							::sprintf(text, "DMR Slot %u, Embedded Talker Alias Header", m_slotNo);
@@ -651,9 +648,9 @@ bool CDMRSlot::writeModem(unsigned char *data, unsigned int len)
 
 					if (!(m_rfTalkerId & TALKER_ID_BLOCK1)) {
 						if (m_rfTalkerId == TALKER_ID_NONE)
-							::memset(m_rfTalkerAlias, '\0', 32U);
-						::memcpy(m_rfTalkerAlias + 6U, data, 7U);
-						m_display->writeDMRTA(m_slotNo, m_rfTalkerAlias, "R");
+							m_rfTalkerAlias.reset();
+						m_rfTalkerAlias.add(1, data, 7U);
+						m_display->writeDMRTA(m_slotNo, (unsigned char*)m_rfTalkerAlias.get(), "R");
 
 						if (m_dumpTAData) {
 							::sprintf(text, "DMR Slot %u, Embedded Talker Alias Block 1", m_slotNo);
@@ -670,9 +667,9 @@ bool CDMRSlot::writeModem(unsigned char *data, unsigned int len)
 
 					if (!(m_rfTalkerId & TALKER_ID_BLOCK2)) {
 						if (m_rfTalkerId == TALKER_ID_NONE)
-							::memset(m_rfTalkerAlias, 0, 32U);
-						::memcpy(m_rfTalkerAlias + 6U + 7U, data, 7U);
-						m_display->writeDMRTA(m_slotNo, m_rfTalkerAlias, "R");
+							m_rfTalkerAlias.reset();
+						m_rfTalkerAlias.add(2, data, 7U);
+						m_display->writeDMRTA(m_slotNo, (unsigned char*)m_rfTalkerAlias.get(), "R");
 
 						if (m_dumpTAData) {
 							::sprintf(text, "DMR Slot %u, Embedded Talker Alias Block 2", m_slotNo);
@@ -689,9 +686,9 @@ bool CDMRSlot::writeModem(unsigned char *data, unsigned int len)
 
 					if (!(m_rfTalkerId & TALKER_ID_BLOCK3)) {
 						if (m_rfTalkerId == TALKER_ID_NONE)
-							::memset(m_rfTalkerAlias, '\0', 32U);
-						::memcpy(m_rfTalkerAlias + 6U + 7U + 7U, data, 7U);
-						m_display->writeDMRTA(m_slotNo, m_rfTalkerAlias, "R");
+							m_rfTalkerAlias.reset();
+						m_rfTalkerAlias.add(3, data, 7U);
+						m_display->writeDMRTA(m_slotNo, (unsigned char*)m_rfTalkerAlias.get(), "R");
 
 						if (m_dumpTAData) {
 							::sprintf(text, "DMR Slot %u, Embedded Talker Alias Block 3", m_slotNo);
@@ -1426,9 +1423,9 @@ void CDMRSlot::writeNetwork(const CDMRData& dmrData)
 			case FLCO_TALKER_ALIAS_HEADER:
 				if (!(m_netTalkerId & TALKER_ID_HEADER)) {
 					if (!m_netTalkerId)
-						::memset(m_rfTalkerAlias, '\0', 32U);
-					::memcpy(m_rfTalkerAlias, data + 2U, 7U);
-					m_display->writeDMRTA(m_slotNo, m_rfTalkerAlias, "N");
+						m_rfTalkerAlias.reset();
+					m_rfTalkerAlias.add(0, data + 2U, 7U);
+					m_display->writeDMRTA(m_slotNo, (unsigned char*)m_rfTalkerAlias.get(), "N");
 
 					if (m_dumpTAData) {
 						::sprintf(text, "DMR Slot %u, Embedded Talker Alias Header", m_slotNo);
@@ -1441,9 +1438,9 @@ void CDMRSlot::writeNetwork(const CDMRData& dmrData)
 			case FLCO_TALKER_ALIAS_BLOCK1:
 				if (!(m_netTalkerId & TALKER_ID_BLOCK1)) {
 					if (!m_netTalkerId)
-						::memset(m_rfTalkerAlias, '\0', 32U);
-					::memcpy(m_rfTalkerAlias + 7U, data + 2U, 7U);
-					m_display->writeDMRTA(m_slotNo, m_rfTalkerAlias, "N");
+						m_rfTalkerAlias.reset();
+					m_rfTalkerAlias.add(1, data + 2U, 7U);
+					m_display->writeDMRTA(m_slotNo, (unsigned char*)m_rfTalkerAlias.get(), "N");
 
 					if (m_dumpTAData) {
 						::sprintf(text, "DMR Slot %u, Embedded Talker Alias Block 1", m_slotNo);
@@ -1456,9 +1453,9 @@ void CDMRSlot::writeNetwork(const CDMRData& dmrData)
 			case FLCO_TALKER_ALIAS_BLOCK2:
 				if (!(m_netTalkerId & TALKER_ID_BLOCK2)) {
 					if (!m_netTalkerId)
-						::memset(m_rfTalkerAlias, '\0', 32U);
-					::memcpy(m_rfTalkerAlias + 7U + 7U, data + 2U, 7U);
-					m_display->writeDMRTA(m_slotNo, m_rfTalkerAlias, "N");
+						m_rfTalkerAlias.reset();
+					m_rfTalkerAlias.add(2, data + 2U, 7U);
+					m_display->writeDMRTA(m_slotNo, (unsigned char*)m_rfTalkerAlias.get(), "N");
 
 					if (m_dumpTAData) {
 						::sprintf(text, "DMR Slot %u, Embedded Talker Alias Block 2", m_slotNo);
@@ -1471,9 +1468,9 @@ void CDMRSlot::writeNetwork(const CDMRData& dmrData)
 			case FLCO_TALKER_ALIAS_BLOCK3:
 				if (!(m_netTalkerId & TALKER_ID_BLOCK3)) {
 					if (!m_netTalkerId)
-						::memset(m_rfTalkerAlias, '\0', 32U);
-					::memcpy(m_rfTalkerAlias + 7U + 7U + 7U, data+2U, 7U);
-					m_display->writeDMRTA(m_slotNo, m_rfTalkerAlias, "N");
+						m_rfTalkerAlias.reset();
+					m_rfTalkerAlias.add(3, data+2U, 7U);
+					m_display->writeDMRTA(m_slotNo, (unsigned char*)m_rfTalkerAlias.get(), "N");
 
 					if (m_dumpTAData) {
 						::sprintf(text, "DMR Slot %u, Embedded Talker Alias Block 3", m_slotNo);
diff --git a/DMRSlot.h b/DMRSlot.h
index ff00617f7..fc01e61ac 100644
--- a/DMRSlot.h
+++ b/DMRSlot.h
@@ -22,6 +22,7 @@
 #include "RSSIInterpolator.h"
 #include "DMREmbeddedData.h"
 #include "DMRNetwork.h"
+#include "DMRTA.h"
 #include "RingBuffer.h"
 #include "StopWatch.h"
 #include "DMRLookup.h"
@@ -69,7 +70,7 @@ class CDMRSlot {
 	unsigned int               m_rfEmbeddedReadN;
 	unsigned int               m_rfEmbeddedWriteN;
 	unsigned char              m_rfTalkerId;
-	unsigned char*             m_rfTalkerAlias;
+	CDMRTA                     m_rfTalkerAlias;
 	CDMREmbeddedData           m_netEmbeddedLC;
 	CDMREmbeddedData*          m_netEmbeddedData;
 	unsigned int               m_netEmbeddedReadN;
diff --git a/DMRTA.cpp b/DMRTA.cpp
new file mode 100644
index 000000000..bf074aa17
--- /dev/null
+++ b/DMRTA.cpp
@@ -0,0 +1,126 @@
+/*
+*	Copyright (C) 2015,2016,2017,2018 Jonathan Naylor, G4KLX
+*	Copyright (C) 2018 by Shawn Chain, BG5HHP
+*
+*	This program is free software; you can redistribute it and/or modify
+*	it under the terms of the GNU General Public License as published by
+*	the Free Software Foundation; version 2 of the License.
+*
+*	This program is distributed in the hope that it will be useful,
+*	but WITHOUT ANY WARRANTY; without even the implied warranty of
+*	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*	GNU General Public License for more details.
+*/
+
+#include "DMRTA.h"
+#include "Log.h"
+
+#include <cstring>
+#include <cassert>
+
+CDMRTA::CDMRTA() :
+m_TA(),
+m_buf()
+{
+}
+
+CDMRTA::~CDMRTA()
+{
+}
+
+bool CDMRTA::add(unsigned int blockId, const unsigned char* data, unsigned int len)
+{
+    assert(data != NULL);
+    if (blockId > 3) {
+        // invalid block id
+        reset();
+        return false;
+    }
+
+    unsigned int offset = blockId * 7;
+
+    if (offset + len >= sizeof(m_buf)) {
+        // buffer overflow
+        reset();
+        return false;
+    }
+
+    ::memcpy(m_buf + offset, data, len);
+
+    return decodeTA();
+}
+
+const unsigned char* CDMRTA::get()
+{
+    return (unsigned char*)m_TA;
+}
+
+void CDMRTA::reset()
+{
+    ::memset(m_TA, 0, sizeof(m_TA));
+    ::memset(m_buf, 0, sizeof(m_buf));
+}
+
+bool CDMRTA::decodeTA()
+{
+    unsigned char *b;
+    unsigned char c;
+    int j;
+    unsigned int i, t1, t2;
+
+    unsigned char* talkerAlias = m_buf;
+
+    unsigned int TAformat = (talkerAlias[0] >> 6U) & 0x03U;
+    unsigned int TAsize   = (talkerAlias[0] >> 1U) & 0x1FU;
+    ::strncpy(m_TA, "(could not decode)", sizeof(m_TA));
+
+    switch (TAformat) {
+	case 0U:		// 7 bit
+		::memset(m_TA, 0, sizeof(m_TA));
+		b = &talkerAlias[0];
+		t1 = 0U; t2 = 0U; c = 0U;
+		for (i = 0U; (i < 32U) && (t2 < TAsize); i++) {
+		    for (j = 7; j >= 0; j--) {
+			    c = (c << 1U) | (b[i] >> j);
+			    if (++t1 == 7U) { 
+                    if (i > 0U)
+                        m_TA[t2++] = c & 0x7FU; 
+
+					t1 = 0U;
+                    c = 0U;
+                }
+		    }
+		}
+        m_TA[TAsize] = 0;
+		break;
+
+	case 1U:		// ISO 8 bit
+	case 2U:		// UTF8
+		::strncpy(m_TA, (char*)talkerAlias + 1U, sizeof(m_TA));
+		break;
+
+	case 3U:		// UTF16 poor man's conversion
+		t2=0;
+		::memset(&m_TA, 0, sizeof(m_TA));
+		for (i = 0U; (i < 15U) && (t2 < TAsize); i++) {
+		    if (talkerAlias[2U * i + 1U] == 0)
+			    m_TA[t2++] = talkerAlias[2U * i + 2U];
+            else
+                m_TA[t2++] = '?';
+		}
+		m_TA[TAsize] = 0;
+		break;
+    }
+
+    size_t TAlen = ::strlen(m_TA);
+    LogMessage("DMR Talker Alias (Data Format %u, Received %u/%u char): '%s'", TAformat, TAlen, TAsize, m_TA);
+
+	if (TAlen > TAsize) {
+        if (TAlen < 29U)
+            strcat(m_TA," ?");
+        else
+            strcpy(m_TA + 28U," ?");
+    }
+
+    return TAlen >= TAsize;
+}
diff --git a/DMRTA.h b/DMRTA.h
new file mode 100644
index 000000000..d53f93f5b
--- /dev/null
+++ b/DMRTA.h
@@ -0,0 +1,35 @@
+/*
+*	Copyright (C) 2015,2016,2017,2018 Jonathan Naylor, G4KLX
+*	Copyright (C) 2018 by Shawn Chain, BG5HHP
+*
+*	This program is free software; you can redistribute it and/or modify
+*	it under the terms of the GNU General Public License as published by
+*	the Free Software Foundation; version 2 of the License.
+*
+*	This program is distributed in the hope that it will be useful,
+*	but WITHOUT ANY WARRANTY; without even the implied warranty of
+*	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*	GNU General Public License for more details.
+*/
+
+#ifndef	DMRTA_H
+#define	DMRTA_H
+
+class CDMRTA {
+public:
+    CDMRTA();
+    ~CDMRTA();
+
+    bool add(unsigned int blockId, const unsigned char* data, unsigned int len);
+    const unsigned char* get();
+    void reset();
+
+protected:
+    bool decodeTA();
+
+private:
+    char            m_TA[32];
+    unsigned char   m_buf[32];
+};
+
+#endif
diff --git a/Display.cpp b/Display.cpp
index 1ee9b647c..24f62f3a2 100644
--- a/Display.cpp
+++ b/Display.cpp
@@ -157,47 +157,8 @@ void CDisplay::writeDMRRSSI(unsigned int slotNo, unsigned char rssi)
 
 void CDisplay::writeDMRTA(unsigned int slotNo, unsigned char* talkerAlias, const char* type)
 {
-    char TA[32U];
-    unsigned char *b;
-    unsigned char c;
-    int j;
-    unsigned int i,t1,t2, TAsize, TAformat;
-
-    if (strcmp(type," ")==0) { writeDMRTAInt(slotNo, (unsigned char*)TA, type); return; }
-
-    TAformat=(talkerAlias[0]>>6U) & 0x03U;
-    TAsize = (talkerAlias[0]>>1U) & 0x1FU;
-    ::strcpy(TA,"(could not decode)");
-    switch (TAformat) {
-	case 0U:		// 7 bit
-		::memset (&TA,0,32U);
-		b=&talkerAlias[0];
-		t1=0; t2=0; c=0;
-		for (i=0;(i<32U)&&(t2<TAsize);i++) {
-		    for (j=7U;j>=0;j--) {
-			c = (c<<1U) | (b[i] >> j);
-			if (++t1==7U) { if (i>0) {TA[t2++]=c & 0x7FU; } t1=0; c=0; }
-		    }
-		}
-		break;
-	case 1U:		// ISO 8 bit
-	case 2U:		// UTF8
-		::strcpy(TA,(char*)talkerAlias+1U);
-		break;
-	case 3U:		// UTF16 poor man's conversion
-		t2=0;
-		::memset (&TA,0,32U);
-		for(i=0;(i<15)&&(t2<TAsize);i++) {
-		    if (talkerAlias[2U*i+1U]==0)
-			TA[t2++]=talkerAlias[2U*i+2U]; else TA[t2++]='?';
-		}
-		TA[TAsize]=0;
-		break;
-    }
-    LogMessage("DMR Talker Alias (Data Format %u, Received %u/%u char): '%s'", TAformat, ::strlen(TA), TAsize, TA);
-    if (::strlen(TA)>TAsize) { if (strlen(TA)<29U) strcat(TA," ?"); else strcpy(TA+28U," ?"); }
-    if (strlen((char*)TA)>=4U) writeDMRTAInt(slotNo, (unsigned char*)TA, type);
-
+    if (strcmp(type," ")==0) { writeDMRTAInt(slotNo, (unsigned char*)"", type); return; }
+    if (strlen((char*)talkerAlias)>=4U) writeDMRTAInt(slotNo, (unsigned char*)talkerAlias, type);
 }
 
 void CDisplay::writeDMRBER(unsigned int slotNo, float ber)
diff --git a/MMDVMHost.cpp b/MMDVMHost.cpp
index 98272e227..07df0295a 100644
--- a/MMDVMHost.cpp
+++ b/MMDVMHost.cpp
@@ -1119,7 +1119,7 @@ bool CMMDVMHost::createModem()
 	LogInfo("    RX Frequency: %uHz (%uHz)", rxFrequency, rxFrequency + rxOffset);
 	LogInfo("    TX Frequency: %uHz (%uHz)", txFrequency, txFrequency + txOffset);
 
-	m_modem = new CModem(port, m_duplex, rxInvert, txInvert, pttInvert, txDelay, dmrDelay, trace, debug);
+	m_modem = CModem::createModem(port, m_duplex, rxInvert, txInvert, pttInvert, txDelay, dmrDelay, trace, debug);
 	m_modem->setSerialParams(protocol,address);
 	m_modem->setModeParams(m_dstarEnabled, m_dmrEnabled, m_ysfEnabled, m_p25Enabled, m_nxdnEnabled, m_pocsagEnabled);
 	m_modem->setLevels(rxLevel, cwIdTXLevel, dstarTXLevel, dmrTXLevel, ysfTXLevel, p25TXLevel, nxdnTXLevel, pocsagTXLevel);
diff --git a/MMDVMHost.vcxproj b/MMDVMHost.vcxproj
index 83cba81f5..90923687d 100644
--- a/MMDVMHost.vcxproj
+++ b/MMDVMHost.vcxproj
@@ -173,6 +173,7 @@
     <ClInclude Include="DMRShortLC.h" />
     <ClInclude Include="DMRSlot.h" />
     <ClInclude Include="DMRSlotType.h" />
+    <ClInclude Include="DMRTA.h" />
     <ClInclude Include="DMRTrellis.h" />
     <ClInclude Include="DStarControl.h" />
     <ClInclude Include="DStarDefines.h" />
@@ -194,6 +195,7 @@
     <ClInclude Include="NetworkInfo.h" />
     <ClInclude Include="Nextion.h" />
     <ClInclude Include="NullDisplay.h" />
+    <ClInclude Include="NullModem.h" />
     <ClInclude Include="NXDNAudio.h" />
     <ClInclude Include="NXDNControl.h" />
     <ClInclude Include="NXDNConvolution.h" />
@@ -263,6 +265,7 @@
     <ClCompile Include="DMRShortLC.cpp" />
     <ClCompile Include="DMRSlot.cpp" />
     <ClCompile Include="DMRSlotType.cpp" />
+    <ClCompile Include="DMRTA.cpp" />
     <ClCompile Include="DMRTrellis.cpp" />
     <ClCompile Include="DStarControl.cpp" />
     <ClCompile Include="DStarHeader.cpp" />
@@ -282,6 +285,7 @@
     <ClCompile Include="NetworkInfo.cpp" />
     <ClCompile Include="Nextion.cpp" />
     <ClCompile Include="NullDisplay.cpp" />
+    <ClCompile Include="NullModem.cpp" />
     <ClCompile Include="NXDNAudio.cpp" />
     <ClCompile Include="NXDNControl.cpp" />
     <ClCompile Include="NXDNConvolution.cpp" />
@@ -327,4 +331,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>
\ No newline at end of file
diff --git a/MMDVMHost.vcxproj.filters b/MMDVMHost.vcxproj.filters
index 200ee2371..0c595bff6 100644
--- a/MMDVMHost.vcxproj.filters
+++ b/MMDVMHost.vcxproj.filters
@@ -278,6 +278,12 @@
     <ClInclude Include="MobileGPS.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="NullModem.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="DMRTA.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="BPTC19696.cpp">
@@ -520,5 +526,11 @@
     <ClCompile Include="MobileGPS.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="NullModem.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="DMRTA.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
-</Project>
+</Project>
\ No newline at end of file
diff --git a/Makefile b/Makefile
index c4d22d500..537fa2e6f 100644
--- a/Makefile
+++ b/Makefile
@@ -8,12 +8,12 @@ LDFLAGS = -g
 
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
-		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
-		DStarSlowData.o Golay2087.o Golay24128.o Hamming.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o NetworkInfo.o \
-		Nextion.o NullDisplay.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o \
-		NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o \
-		POCSAGNetwork.o QR1676.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o SHA256.o StopWatch.o Sync.o TFTSerial.o Thread.o \
-		Timer.o UDPSocket.o UMP.o Utils.o YSFControl.o YSFConvolution.o YSFFICH.o YSFNetwork.o YSFPayload.o
+		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
+		DStarSlowData.o Golay2087.o Golay24128.o Hamming.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o \
+		NetworkInfo.o Nextion.o NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o \
+		NXDNLookup.o NXDNNetwork.o NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o \
+		POCSAGControl.o POCSAGNetwork.o QR1676.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o SHA256.o StopWatch.o Sync.o TFTSerial.o \
+		Thread.o Timer.o UDPSocket.o UMP.o Utils.o YSFControl.o YSFConvolution.o YSFFICH.o YSFNetwork.o YSFPayload.o
 
 all:		MMDVMHost
 
diff --git a/Makefile.Pi b/Makefile.Pi
index dc8e1aa4e..2f5de8f93 100644
--- a/Makefile.Pi
+++ b/Makefile.Pi
@@ -8,12 +8,12 @@ LDFLAGS = -g -L/usr/local/lib
 
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
-		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
-		DStarSlowData.o Golay2087.o Golay24128.o Hamming.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o NetworkInfo.o Nextion.o \
-		NullDisplay.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o NXDNSACCH.o \
-		NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o POCSAGNetwork.o \
-		QR1676.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o SHA256.o StopWatch.o Sync.o TFTSerial.o Thread.o Timer.o UDPSocket.o \
-		UMP.o Utils.o YSFControl.o YSFConvolution.o YSFFICH.o YSFNetwork.o YSFPayload.o
+		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
+		DStarSlowData.o Golay2087.o Golay24128.o Hamming.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o \
+		NetworkInfo.o Nextion.o NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o \
+		NXDNNetwork.o NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o \
+		POCSAGNetwork.o QR1676.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o SHA256.o StopWatch.o Sync.o TFTSerial.o Thread.o Timer.o \
+		UDPSocket.o UMP.o Utils.o YSFControl.o YSFConvolution.o YSFFICH.o YSFNetwork.o YSFPayload.o
 
 all:		MMDVMHost
 
diff --git a/Makefile.Pi.Adafruit b/Makefile.Pi.Adafruit
index 1065ed3c2..fc6df1669 100644
--- a/Makefile.Pi.Adafruit
+++ b/Makefile.Pi.Adafruit
@@ -8,10 +8,10 @@ LDFLAGS = -g -L/usr/local/lib
 
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
-		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
-		DStarSlowData.o Golay2087.o Golay24128.o Hamming.o HD44780.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o NetworkInfo.o \
-		Nextion.o NullDisplay.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o \
-		NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o \
+		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
+		DStarSlowData.o Golay2087.o Golay24128.o Hamming.o HD44780.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o \
+		NetworkInfo.o Nextion.o NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o \
+		NXDNNetwork.o NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o \
 		POCSAGNetwork.o QR1676.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o SHA256.o StopWatch.o Sync.o TFTSerial.o Thread.o \
 		Timer.o UDPSocket.o UMP.o Utils.o YSFControl.o YSFConvolution.o YSFFICH.o YSFNetwork.o YSFPayload.o
 
diff --git a/Makefile.Pi.HD44780 b/Makefile.Pi.HD44780
index fd3c32f0e..124629777 100644
--- a/Makefile.Pi.HD44780
+++ b/Makefile.Pi.HD44780
@@ -8,10 +8,10 @@ LDFLAGS = -g -L/usr/local/lib
 
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
-		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
-		DStarSlowData.o Golay2087.o Golay24128.o Hamming.o HD44780.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o NetworkInfo.o \
-		Nextion.o NullDisplay.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o \
-		NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o \
+		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
+		DStarSlowData.o Golay2087.o Golay24128.o Hamming.o HD44780.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o \
+		NetworkInfo.o Nextion.o NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o \
+		NXDNNetwork.o NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o \
 		POCSAGNetwork.o QR1676.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o SHA256.o StopWatch.o Sync.o TFTSerial.o Thread.o \
 		Timer.o UDPSocket.o UMP.o Utils.o YSFControl.o YSFConvolution.o YSFFICH.o YSFNetwork.o YSFPayload.o
 
diff --git a/Makefile.Pi.OLED b/Makefile.Pi.OLED
index 9c17f0660..2c4516573 100644
--- a/Makefile.Pi.OLED
+++ b/Makefile.Pi.OLED
@@ -8,10 +8,10 @@ LDFLAGS = -g -L/usr/local/lib
 
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
-		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
-		DStarSlowData.o Golay2087.o Golay24128.o Hamming.o I2CController.o OLED.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o NetworkInfo.o \
-		Nextion.o NullDisplay.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o \
-		NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o \
+		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
+		DStarSlowData.o Golay2087.o Golay24128.o Hamming.o I2CController.o OLED.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o \
+		NetworkInfo.o Nextion.o NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o \
+		NXDNNetwork.o NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o \
 		POCSAGNetwork.o QR1676.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o SHA256.o StopWatch.o Sync.o TFTSerial.o Thread.o \
 		Timer.o UDPSocket.o UMP.o Utils.o YSFControl.o YSFConvolution.o YSFFICH.o YSFNetwork.o YSFPayload.o
 
diff --git a/Makefile.Pi.PCF8574 b/Makefile.Pi.PCF8574
index 29dba7c2d..30aaf248d 100644
--- a/Makefile.Pi.PCF8574
+++ b/Makefile.Pi.PCF8574
@@ -8,10 +8,10 @@ LDFLAGS = -g -L/usr/local/lib
 
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
-		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
-		DStarSlowData.o Golay2087.o Golay24128.o Hamming.o HD44780.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o NetworkInfo.o \
-		Nextion.o NullDisplay.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o \
-		NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o \
+		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
+		DStarSlowData.o Golay2087.o Golay24128.o Hamming.o HD44780.o I2CController.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o \
+		NetworkInfo.o Nextion.o NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o \
+		NXDNNetwork.o NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o \
 		POCSAGNetwork.o QR1676.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o SHA256.o StopWatch.o Sync.o TFTSerial.o Thread.o \
 		Timer.o UDPSocket.o UMP.o Utils.o YSFControl.o YSFConvolution.o YSFFICH.o YSFNetwork.o YSFPayload.o
 
diff --git a/Makefile.Solaris b/Makefile.Solaris
index b82ee32f8..b701271d0 100644
--- a/Makefile.Solaris
+++ b/Makefile.Solaris
@@ -8,10 +8,10 @@ LDFLAGS = -g
 
 OBJECTS = \
 		AMBEFEC.o BCH.o BPTC19696.o Conf.o CRC.o Display.o DMRControl.o DMRCSBK.o DMRData.o DMRDataHeader.o DMREMB.o DMREmbeddedData.o DMRFullLC.o \
-		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
+		DMRLookup.o DMRLC.o DMRNetwork.o DMRShortLC.o DMRSlot.o DMRSlotType.o DMRAccessControl.o DMRTA.o DMRTrellis.o DStarControl.o DStarHeader.o DStarNetwork.o \
 		DStarSlowData.o Golay2087.o Golay24128.o Hamming.o LCDproc.o Log.o MMDVMHost.o MobileGPS.o Modem.o ModemSerialPort.o Mutex.o NetworkInfo.o Nextion.o \
-		NullDisplay.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o NXDNSACCH.o \
-		NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o POCSAGNetwork.o \
+		NullDisplay.o NullModem.o NXDNAudio.o NXDNControl.o NXDNConvolution.o NXDNCRC.o NXDNFACCH1.o NXDNLayer3.o NXDNLICH.o NXDNLookup.o NXDNNetwork.o \
+		NXDNSACCH.o NXDNUDCH.o P25Audio.o P25Control.o P25Data.o P25LowSpeedData.o P25Network.o P25NID.o P25Trellis.o P25Utils.o POCSAGControl.o POCSAGNetwork.o \
 		QR1676.o RS129.o RS241213.o RSSIInterpolator.o SerialController.o SerialPort.o SHA256.o StopWatch.o Sync.o TFTSerial.o Thread.o Timer.o UDPSocket.o \
 		UMP.o Utils.o YSFControl.o YSFConvolution.o YSFFICH.o YSFNetwork.o YSFPayload.o
 
diff --git a/Modem.cpp b/Modem.cpp
index ae7ca762c..7fe5ae172 100644
--- a/Modem.cpp
+++ b/Modem.cpp
@@ -25,6 +25,7 @@
 #include "POCSAGDefines.h"
 #include "Thread.h"
 #include "Modem.h"
+#include "NullModem.h"
 #include "Utils.h"
 #include "Log.h"
 
@@ -1830,3 +1831,10 @@ void CModem::printDebug()
 		LogMessage("Debug: %.*s %d %d %d %d", m_length - 11U, m_buffer + 3U, val1, val2, val3, val4);
 	}
 }
+
+CModem* CModem::createModem(const std::string& port, bool duplex, bool rxInvert, bool txInvert, bool pttInvert, unsigned int txDelay, unsigned int dmrDelay, bool trace, bool debug){
+	if (port == "NullModem")
+		return new CNullModem(port, duplex, rxInvert, txInvert, pttInvert, txDelay, dmrDelay, trace, debug);
+	else
+		return new CModem(port, duplex, rxInvert, txInvert, pttInvert, txDelay, dmrDelay, trace, debug);
+}
\ No newline at end of file
diff --git a/Modem.h b/Modem.h
index 9c8b6c0dc..30af40183 100644
--- a/Modem.h
+++ b/Modem.h
@@ -35,75 +35,77 @@ enum RESP_TYPE_MMDVM {
 class CModem {
 public:
 	CModem(const std::string& port, bool duplex, bool rxInvert, bool txInvert, bool pttInvert, unsigned int txDelay, unsigned int dmrDelay, bool trace, bool debug);
-	~CModem();
+	virtual ~CModem();
 
-	void setSerialParams(const std::string& protocol, unsigned int address);
-	void setRFParams(unsigned int rxFrequency, int rxOffset, unsigned int txFrequency, int txOffset, int txDCOffset, int rxDCOffset, float rfLevel, unsigned int pocsagFrequency);
-	void setModeParams(bool dstarEnabled, bool dmrEnabled, bool ysfEnabled, bool p25Enabled, bool nxdnEnabled, bool pocsagEnabled);
-	void setLevels(float rxLevel, float cwIdTXLevel, float dstarTXLevel, float dmrTXLevel, float ysfTXLevel, float p25TXLevel, float nxdnTXLevel, float pocsagLevel);
-	void setDMRParams(unsigned int colorCode);
-	void setYSFParams(bool loDev, unsigned int txHang);
-	void setTransparentDataParams(unsigned int sendFrameType);
+	virtual void setSerialParams(const std::string& protocol, unsigned int address);
+	virtual void setRFParams(unsigned int rxFrequency, int rxOffset, unsigned int txFrequency, int txOffset, int txDCOffset, int rxDCOffset, float rfLevel, unsigned int pocsagFrequency);
+	virtual void setModeParams(bool dstarEnabled, bool dmrEnabled, bool ysfEnabled, bool p25Enabled, bool nxdnEnabled, bool pocsagEnabled);
+	virtual void setLevels(float rxLevel, float cwIdTXLevel, float dstarTXLevel, float dmrTXLevel, float ysfTXLevel, float p25TXLevel, float nxdnTXLevel, float pocsagLevel);
+	virtual void setDMRParams(unsigned int colorCode);
+	virtual void setYSFParams(bool loDev, unsigned int txHang);
+	virtual void setTransparentDataParams(unsigned int sendFrameType);
 
-	bool open();
+	virtual bool open();
 
-	unsigned int readDStarData(unsigned char* data);
-	unsigned int readDMRData1(unsigned char* data);
-	unsigned int readDMRData2(unsigned char* data);
-	unsigned int readYSFData(unsigned char* data);
-	unsigned int readP25Data(unsigned char* data);
-	unsigned int readNXDNData(unsigned char* data);
-	unsigned int readTransparentData(unsigned char* data);
+	virtual unsigned int readDStarData(unsigned char* data);
+	virtual unsigned int readDMRData1(unsigned char* data);
+	virtual unsigned int readDMRData2(unsigned char* data);
+	virtual unsigned int readYSFData(unsigned char* data);
+	virtual unsigned int readP25Data(unsigned char* data);
+	virtual unsigned int readNXDNData(unsigned char* data);
+	virtual unsigned int readTransparentData(unsigned char* data);
 
-	unsigned int readSerial(unsigned char* data, unsigned int length);
+	virtual unsigned int readSerial(unsigned char* data, unsigned int length);
 
-	bool hasDStarSpace() const;
-	bool hasDMRSpace1() const;
-	bool hasDMRSpace2() const;
-	bool hasYSFSpace() const;
-	bool hasP25Space() const;
-	bool hasNXDNSpace() const;
-	bool hasPOCSAGSpace() const;
+	virtual bool hasDStarSpace() const;
+	virtual bool hasDMRSpace1() const;
+	virtual bool hasDMRSpace2() const;
+	virtual bool hasYSFSpace() const;
+	virtual bool hasP25Space() const;
+	virtual bool hasNXDNSpace() const;
+	virtual bool hasPOCSAGSpace() const;
 
-	bool hasTX() const;
-	bool hasCD() const;
+	virtual bool hasTX() const;
+	virtual bool hasCD() const;
 
-	bool hasLockout() const;
-	bool hasError() const;
+	virtual bool hasLockout() const;
+	virtual bool hasError() const;
 
-	bool writeDStarData(const unsigned char* data, unsigned int length);
-	bool writeDMRData1(const unsigned char* data, unsigned int length);
-	bool writeDMRData2(const unsigned char* data, unsigned int length);
-	bool writeYSFData(const unsigned char* data, unsigned int length);
-	bool writeP25Data(const unsigned char* data, unsigned int length);
-	bool writeNXDNData(const unsigned char* data, unsigned int length);
-	bool writePOCSAGData(const unsigned char* data, unsigned int length);
+	virtual bool writeDStarData(const unsigned char* data, unsigned int length);
+	virtual bool writeDMRData1(const unsigned char* data, unsigned int length);
+	virtual bool writeDMRData2(const unsigned char* data, unsigned int length);
+	virtual bool writeYSFData(const unsigned char* data, unsigned int length);
+	virtual bool writeP25Data(const unsigned char* data, unsigned int length);
+	virtual bool writeNXDNData(const unsigned char* data, unsigned int length);
+	virtual bool writePOCSAGData(const unsigned char* data, unsigned int length);
 
-	bool writeTransparentData(const unsigned char* data, unsigned int length);
+	virtual bool writeTransparentData(const unsigned char* data, unsigned int length);
 
-	bool writeDStarInfo(const char* my1, const char* my2, const char* your, const char* type, const char* reflector);
-	bool writeDMRInfo(unsigned int slotNo, const std::string& src, bool group, const std::string& dst, const char* type);
-	bool writeYSFInfo(const char* source, const char* dest, const char* type, const char* origin);
-	bool writeP25Info(const char* source, bool group, unsigned int dest, const char* type);
-	bool writeNXDNInfo(const char* source, bool group, unsigned int dest, const char* type);
-	bool writePOCSAGInfo(unsigned int ric, const std::string& message);
-	bool writeIPInfo(const std::string& address);
+	virtual bool writeDStarInfo(const char* my1, const char* my2, const char* your, const char* type, const char* reflector);
+	virtual bool writeDMRInfo(unsigned int slotNo, const std::string& src, bool group, const std::string& dst, const char* type);
+	virtual bool writeYSFInfo(const char* source, const char* dest, const char* type, const char* origin);
+	virtual bool writeP25Info(const char* source, bool group, unsigned int dest, const char* type);
+	virtual bool writeNXDNInfo(const char* source, bool group, unsigned int dest, const char* type);
+	virtual bool writePOCSAGInfo(unsigned int ric, const std::string& message);
+	virtual bool writeIPInfo(const std::string& address);
 
-	bool writeDMRStart(bool tx);
-	bool writeDMRShortLC(const unsigned char* lc);
-	bool writeDMRAbort(unsigned int slotNo);
+	virtual bool writeDMRStart(bool tx);
+	virtual bool writeDMRShortLC(const unsigned char* lc);
+	virtual bool writeDMRAbort(unsigned int slotNo);
 
-	bool writeSerial(const unsigned char* data, unsigned int length);
+	virtual bool writeSerial(const unsigned char* data, unsigned int length);
 
-	bool setMode(unsigned char mode);
+	virtual bool setMode(unsigned char mode);
 
-	bool sendCWId(const std::string& callsign);
+	virtual bool sendCWId(const std::string& callsign);
 
-	HW_TYPE getHWType() const;
+	virtual HW_TYPE getHWType() const;
 
-	void clock(unsigned int ms);
+	virtual void clock(unsigned int ms);
 
-	void close();
+	virtual void close();
+
+	static CModem* createModem(const std::string& port, bool duplex, bool rxInvert, bool txInvert, bool pttInvert, unsigned int txDelay, unsigned int dmrDelay, bool trace, bool debug);
 
 private:
 	std::string                m_port;
diff --git a/NullModem.cpp b/NullModem.cpp
new file mode 100644
index 000000000..8539f1b6b
--- /dev/null
+++ b/NullModem.cpp
@@ -0,0 +1,35 @@
+/*
+ *   Copyright (C) 2011-2018 by Jonathan Naylor G4KLX
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "NullModem.h"
+#include "Log.h"
+
+CNullModem::CNullModem(const std::string& port, bool duplex, bool rxInvert, bool txInvert, bool pttInvert, unsigned int txDelay, unsigned int dmrDelay, bool trace, bool debug) :
+CModem(port, duplex,rxInvert, txInvert,pttInvert,txDelay, dmrDelay, trace, debug),
+m_hwType(HWT_MMDVM)
+{
+}
+
+CNullModem::~CNullModem()
+{
+}
+
+bool CNullModem::open(){
+	::LogMessage("Opening the MMDVM Null Modem");
+	return true;
+}
\ No newline at end of file
diff --git a/NullModem.h b/NullModem.h
new file mode 100644
index 000000000..2698f47f6
--- /dev/null
+++ b/NullModem.h
@@ -0,0 +1,105 @@
+/*
+ *   Copyright (C) 2011-2018 by Jonathan Naylor G4KLX
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef	NULLMODEM_H
+#define	NULLMODEM_H
+
+#include "Modem.h"
+#include "Defines.h"
+
+#include <string>
+
+
+class CNullModem : public CModem {
+public:
+	CNullModem(const std::string& port, bool duplex, bool rxInvert, bool txInvert, bool pttInvert, unsigned int txDelay, unsigned int dmrDelay, bool trace, bool debug);
+	virtual ~CNullModem();
+
+	virtual void setSerialParams(const std::string& protocol, unsigned int address){};
+	virtual void setRFParams(unsigned int rxFrequency, int rxOffset, unsigned int txFrequency, int txOffset, int txDCOffset, int rxDCOffset, float rfLevel, unsigned int pocsagFrequency){};
+	virtual void setModeParams(bool dstarEnabled, bool dmrEnabled, bool ysfEnabled, bool p25Enabled, bool nxdnEnabled, bool pocsagEnabled){};
+	virtual void setLevels(float rxLevel, float cwIdTXLevel, float dstarTXLevel, float dmrTXLevel, float ysfTXLevel, float p25TXLevel, float nxdnTXLevel, float pocsagLevel){};
+	virtual void setDMRParams(unsigned int colorCode){};
+	virtual void setYSFParams(bool loDev, unsigned int txHang){};
+	virtual void setTransparentDataParams(unsigned int sendFrameType){};
+
+	virtual bool open();
+
+	virtual unsigned int readDStarData(unsigned char* data){return 0;};
+	virtual unsigned int readDMRData1(unsigned char* data){return 0;};
+	virtual unsigned int readDMRData2(unsigned char* data){return 0;};
+	virtual unsigned int readYSFData(unsigned char* data){return 0;};
+	virtual unsigned int readP25Data(unsigned char* data){return 0;};
+	virtual unsigned int readNXDNData(unsigned char* data){return 0;};
+	virtual unsigned int readTransparentData(unsigned char* data){return 0;};
+
+	virtual unsigned int readSerial(unsigned char* data, unsigned int length){return 0;};
+
+	virtual bool hasDStarSpace()const {return true;};
+	virtual bool hasDMRSpace1() const {return true;};
+	virtual bool hasDMRSpace2() const {return true;};
+	virtual bool hasYSFSpace() const  {return true;};
+	virtual bool hasP25Space() const  {return true;};
+	virtual bool hasNXDNSpace() const {return true;};
+	virtual bool hasPOCSAGSpace() const{return true;}; 
+
+	virtual bool hasTX() const {return false;};
+	virtual bool hasCD() const {return false;};
+
+	virtual bool hasLockout() const {return false;};
+	virtual bool hasError() const   {return false;};
+
+	virtual bool writeDStarData(const unsigned char* data, unsigned int length){return true;};
+	virtual bool writeDMRData1(const unsigned char* data, unsigned int length){return true;};
+	virtual bool writeDMRData2(const unsigned char* data, unsigned int length){return true;};
+	virtual bool writeYSFData(const unsigned char* data, unsigned int length){return true;};
+	virtual bool writeP25Data(const unsigned char* data, unsigned int length){return true;};
+	virtual bool writeNXDNData(const unsigned char* data, unsigned int length){return true;};
+	virtual bool writePOCSAGData(const unsigned char* data, unsigned int length){return true;};
+
+	virtual bool writeTransparentData(const unsigned char* data, unsigned int length){return true;};
+
+	virtual bool writeDStarInfo(const char* my1, const char* my2, const char* your, const char* type, const char* reflector){return true;};
+	virtual bool writeDMRInfo(unsigned int slotNo, const std::string& src, bool group, const std::string& dst, const char* type){return true;};
+	virtual bool writeYSFInfo(const char* source, const char* dest, const char* type, const char* origin){return true;};
+	virtual bool writeP25Info(const char* source, bool group, unsigned int dest, const char* type){return true;};
+	virtual bool writeNXDNInfo(const char* source, bool group, unsigned int dest, const char* type){return true;};
+	virtual bool writePOCSAGInfo(unsigned int ric, const std::string& message){return true;};
+	virtual bool writeIPInfo(const std::string& address){return true;};
+
+	virtual bool writeDMRStart(bool tx){return true;};
+	virtual bool writeDMRShortLC(const unsigned char* lc){return true;};
+	virtual bool writeDMRAbort(unsigned int slotNo){return true;};
+
+	virtual bool writeSerial(const unsigned char* data, unsigned int length){return true;};
+
+	virtual bool setMode(unsigned char mode){return true;};
+
+	virtual bool sendCWId(const std::string& callsign){return true;};
+
+	virtual HW_TYPE getHWType() const {return m_hwType;};
+
+	virtual void clock(unsigned int ms){};
+
+	virtual void close(){};
+
+private:
+	HW_TYPE                    m_hwType;
+};
+
+#endif
diff --git a/YSFControl.cpp b/YSFControl.cpp
index fdd0c961e..79237a061 100644
--- a/YSFControl.cpp
+++ b/YSFControl.cpp
@@ -182,6 +182,7 @@ bool CYSFControl::writeModem(unsigned char *data, unsigned int len)
 		}
 	}
 
+#ifdef notdef
 	// Stop repeater packets coming through, unless we're acting as a remote gateway
 	if (m_remoteGateway) {
 		unsigned char mr = m_lastFICH.getMR();
@@ -192,6 +193,7 @@ bool CYSFControl::writeModem(unsigned char *data, unsigned int len)
 		if (mr == YSF_MR_BUSY)
 			return false;
 	}
+#endif
 
 	unsigned char dt = m_lastFICH.getDT();