diff --git a/Defines.h b/Defines.h
index f87ca05..138451a 100644
--- a/Defines.h
+++ b/Defines.h
@@ -144,4 +144,8 @@ const uint8_t BIT_MASK_TABLE[] = { 0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x0
 #define _WRITE_BIT(p, i, b) p[(i) >> 3] = (b) ? (p[(i) >> 3] | BIT_MASK_TABLE[(i) & 7]) : (p[(i)>>3] & ~BIT_MASK_TABLE[(i) & 7])
 #define _READ_BIT(p, i)     ((p[(i) >> 3] & BIT_MASK_TABLE[(i) & 7]) >> (7 - ((i) & 7)))
 
+#if !defined(ENABLE_DMR) && !defined(ENABLE_P25) && !defined(ENABLE_NXDN)
+#error "No protocol support compiled in? Must enable at least one: ENABLE_DMR, ENABLE_P25 and/or ENABLE_NXDN."
+#endif
+
 #endif // __DEFINES_H__
diff --git a/FirmwareMain.cpp b/FirmwareMain.cpp
index a63dea8..a0e5a35 100644
--- a/FirmwareMain.cpp
+++ b/FirmwareMain.cpp
@@ -66,6 +66,7 @@ bool m_dcd = false;
 uint8_t m_control;
 
 /** DMR BS */
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
 dmr::DMRIdleRX dmrIdleRX;
 dmr::DMRRX dmrRX;
@@ -75,19 +76,30 @@ dmr::DMRTX dmrTX;
 /** DMR MS-DMO */
 dmr::DMRDMORX dmrDMORX;
 dmr::DMRDMOTX dmrDMOTX;
+#endif
 
 /** P25 */
+#if defined(ENABLE_P25)
 p25::P25RX p25RX;
 p25::P25TX p25TX;
+#endif
 
 /** NXDN */
+#if defined(ENABLE_NXDN)
 nxdn::NXDNRX nxdnRX;
 nxdn::NXDNTX nxdnTX;
+#endif
 
 /** Calibration */
+#if defined(ENABLE_DMR)
 dmr::CalDMR calDMR;
+#endif
+#if defined(ENABLE_P25)
 p25::CalP25 calP25;
+#endif
+#if defined(ENABLE_NXDN)
 nxdn::CalNXDN calNXDN;
+#endif
 CalRSSI calRSSI;
 
 /** CW */
@@ -113,6 +125,7 @@ void loop()
     io.process();
 
     // The following is for transmitting
+#if defined(ENABLE_DMR)
     if (m_dmrEnable && m_modemState == STATE_DMR) {
 #if defined(DUPLEX)
         if (m_duplex)
@@ -121,25 +134,36 @@ void loop()
             dmrDMOTX.process();
 #else
         dmrDMOTX.process();
-#endif
+#endif // defined(DUPLEX)
     }
+#endif // defined(ENABLE_DMR)
 
+#if defined(ENABLE_P25)
     if (m_p25Enable && m_modemState == STATE_P25)
         p25TX.process();
+#endif // defined(ENABLE_P25)
 
+#if defined(ENABLE_NXDN)
     if (m_nxdnEnable && m_modemState == STATE_NXDN)
         nxdnTX.process();
+#endif // defined(ENABLE_NXDN)
 
+#if defined(ENABLE_DMR)
     if (m_modemState == STATE_DMR_DMO_CAL_1K || m_modemState == STATE_DMR_CAL_1K ||
         m_modemState == STATE_DMR_LF_CAL || m_modemState == STATE_DMR_CAL ||
         m_modemState == STATE_INT_CAL)
         calDMR.process();
+#endif // defined(ENABLE_DMR)
 
+#if defined(ENABLE_P25)
     if (m_modemState == STATE_P25_CAL_1K || m_modemState == STATE_P25_CAL)
         calP25.process();
+#endif // defined(ENABLE_P25)
 
+#if defined(ENABLE_NXDN)
     if (m_modemState == STATE_NXDN_CAL)
         calNXDN.process();
+#endif // defined(ENABLE_NXDN)
 
     if (m_modemState == STATE_RSSI_CAL)
         calRSSI.process();
diff --git a/Globals.h b/Globals.h
index b1e18c9..022afba 100644
--- a/Globals.h
+++ b/Globals.h
@@ -110,28 +110,40 @@ extern SerialPort serial;
 extern IO io;
 
 /** DMR BS */
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
 extern dmr::DMRIdleRX dmrIdleRX;
 extern dmr::DMRRX dmrRX;
-#endif
+#endif // defined(DUPLEX)
 extern dmr::DMRTX dmrTX;
 
 /** DMR MS-DMO */
 extern dmr::DMRDMORX dmrDMORX;
 extern dmr::DMRDMOTX dmrDMOTX;
+#endif // defined(ENABLE_DMR)
 
 /** P25 BS */
+#if defined(ENABLE_P25)
 extern p25::P25RX p25RX;
 extern p25::P25TX p25TX;
+#endif // defined(ENABLE_P25)
 
 /** NXDN BS */
+#if defined(ENABLE_NXDN)
 extern nxdn::NXDNRX nxdnRX;
 extern nxdn::NXDNTX nxdnTX;
+#endif // defined(ENABLE_NXDN)
 
 /** Calibration */
+#if defined(ENABLE_DMR)
 extern dmr::CalDMR calDMR;
+#endif // defined(ENABLE_DMR)
+#if defined(ENABLE_P25)
 extern p25::CalP25 calP25;
+#endif // defined(ENABLE_P25)
+#if defined(ENABLE_NXDN)
 extern nxdn::CalNXDN calNXDN;
+#endif // defined(ENABLE_NXDN)
 extern CalRSSI calRSSI;
 
 /** CW */
diff --git a/IO.cpp b/IO.cpp
index 9e5e155..f432e3e 100644
--- a/IO.cpp
+++ b/IO.cpp
@@ -145,6 +145,7 @@ void IO::process()
         m_rxBuffer.get(bit, control);
 
         if (m_modemState == STATE_DMR) {
+#if defined(ENABLE_DMR)            
             /** Digital Mobile Radio */
 #if defined(DUPLEX)
             if (m_duplex) {
@@ -157,15 +158,20 @@ void IO::process()
                 dmrDMORX.databit(bit);
 #else
             dmrDMORX.databit(bit);
-#endif
+#endif // defined(DUPLEX)
+#endif // defined(ENABLE_DMR)
         }
         else if (m_modemState == STATE_P25) {
+#if defined(ENABLE_P25)
             /** Project 25 */
             p25RX.databit(bit);
+#endif // defined(ENABLE_P25)
         }
         else if (m_modemState == STATE_NXDN) {
+#if defined(ENABLE_NXDN)
             /** Next Generation Digital Narrowband */
             nxdnRX.databit(bit);
+#endif // defined(ENABLE_NXDN)
         }
     }
 }
diff --git a/SerialPort.cpp b/SerialPort.cpp
index 0d24308..035d965 100644
--- a/SerialPort.cpp
+++ b/SerialPort.cpp
@@ -198,13 +198,20 @@ void SerialPort::process()
                     break;
 
                 case CMD_CAL_DATA:
+                    err = RSN_NAK;
+#if defined(ENABLE_DMR)
                     if (m_modemState == STATE_DMR_DMO_CAL_1K || m_modemState == STATE_DMR_CAL_1K ||
                         m_modemState == STATE_DMR_LF_CAL || m_modemState == STATE_DMR_CAL)
                         err = calDMR.write(m_buffer + 3U, m_len - 3U);
+#endif // defined(ENABLE_DMR)
+#if defined(ENABLE_P25)
                     if (m_modemState == STATE_P25_CAL_1K || m_modemState == STATE_P25_CAL)
                         err = calP25.write(m_buffer + 3U, m_len - 3U);
+#endif // defined(ENABLE_P25)
+#if defined(ENABLE_P25)
                     if (m_modemState == STATE_NXDN_CAL)
                         err = calNXDN.write(m_buffer + 3U, m_len - 3U);
+#endif // defined(ENABLE_P25)
                     if (err == RSN_OK)
                     {
                         sendACK();
@@ -249,6 +256,7 @@ void SerialPort::process()
 
                 /** Digital Mobile Radio */
                 case CMD_DMR_DATA1:
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
                     if (m_dmrEnable) {
                         if (m_modemState == STATE_IDLE || m_modemState == STATE_DMR) {
@@ -266,10 +274,15 @@ void SerialPort::process()
                     }
 #else
                     sendNAK(RSN_INVALID_REQUEST);
-#endif
+#endif // defined(DUPLEX)
+#else
+                    DEBUG2("SerialPort: process() received invalid DMR data", err);
+                    sendNAK(err);
+#endif // defined(ENABLE_DMR)
                     break;
 
                 case CMD_DMR_DATA2:
+#if defined(ENABLE_DMR)
                     if (m_dmrEnable) {
                         if (m_modemState == STATE_IDLE || m_modemState == STATE_DMR) {
 #if defined(DUPLEX)
@@ -279,9 +292,12 @@ void SerialPort::process()
                                 err = dmrDMOTX.writeData(m_buffer + 3U, m_len - 3U);
 #else
                             err = dmrDMOTX.writeData(m_buffer + 3U, m_len - 3U);
-#endif
+#endif // defined(DUPLEX)
                         }
                     }
+#else
+                    err = RSN_NAK;
+#endif // defined(ENABLE_DMR)
                     if (err == RSN_OK) {
                         if (m_modemState == STATE_IDLE)
                             setMode(STATE_DMR);
@@ -293,6 +309,7 @@ void SerialPort::process()
                     break;
 
                 case CMD_DMR_START:
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
                     if (m_dmrEnable) {
                         err = RSN_INVALID_DMR_START;
@@ -315,10 +332,14 @@ void SerialPort::process()
                     }
 #else
                     sendNAK(RSN_INVALID_REQUEST);
-#endif
+#endif // defined(DUPLEX)
+#else
+                    sendNAK(RSN_INVALID_REQUEST);
+#endif // defined(ENABLE_DMR)
                     break;
 
                 case CMD_DMR_SHORTLC:
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
                     if (m_dmrEnable)
                         err = dmrTX.writeShortLC(m_buffer + 3U, m_len - 3U);
@@ -328,10 +349,14 @@ void SerialPort::process()
                     }
 #else
                     sendNAK(RSN_INVALID_REQUEST);
-#endif
+#endif // defined(DUPLEX)
+#else
+                    sendNAK(RSN_INVALID_REQUEST);
+#endif // defined(ENABLE_DMR)
                     break;
 
                 case CMD_DMR_ABORT:
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
                     if (m_dmrEnable)
                         err = dmrTX.writeAbort(m_buffer + 3U, m_len - 3U);
@@ -341,10 +366,14 @@ void SerialPort::process()
                     }
 #else
                     sendNAK(RSN_INVALID_REQUEST);
-#endif
+#endif // defined(DUPLEX)
+#else
+                    sendNAK(RSN_INVALID_REQUEST);
+#endif // defined(ENABLE_DMR)
                     break;
 
                 case CMD_DMR_CACH_AT_CTRL:
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
                     if (m_dmrEnable) {
                         err = RSN_INVALID_REQUEST;
@@ -359,11 +388,15 @@ void SerialPort::process()
                     }
 #else
                     sendNAK(RSN_INVALID_REQUEST);
-#endif
+#endif // defined(DUPLEX)
+#else
+                    sendNAK(RSN_INVALID_REQUEST);
+#endif // defined(ENABLE_DMR)
                     break;
 
                 /** Project 25 */
                 case CMD_P25_DATA:
+#if defined(ENABLE_P25)
                     if (m_p25Enable) {
                         if (m_modemState == STATE_IDLE || m_modemState == STATE_P25)
                             err = p25TX.writeData(m_buffer + 3U, m_len - 3U);
@@ -376,17 +409,25 @@ void SerialPort::process()
                         DEBUG2("SerialPort: process(): Received invalid P25 data", err);
                         sendNAK(err);
                     }
+#else
+                    sendNAK(RSN_INVALID_REQUEST);
+#endif // defined(ENABLE_P25)
                     break;
 
                 case CMD_P25_CLEAR:
+#if defined(ENABLE_P25)
                     if (m_p25Enable) {
                         if (m_modemState == STATE_IDLE || m_modemState == STATE_P25)
                             p25TX.clear();
                     }
+#else
+                    sendNAK(RSN_INVALID_REQUEST);
+#endif // defined(ENABLE_P25)
                     break;
 
                 /** Next Generation Digital Narrowband */
                 case CMD_NXDN_DATA:
+#if defined(ENABLE_NXDN)
                     if (m_nxdnEnable) {
                         if (m_modemState == STATE_IDLE || m_modemState == STATE_NXDN)
                             err = nxdnTX.writeData(m_buffer + 3U, m_len - 3U);
@@ -399,6 +440,9 @@ void SerialPort::process()
                         DEBUG2("SerialPort: process(): Received invalid NXDN data", err);
                         sendNAK(err);
                     }
+#else
+                    sendNAK(RSN_INVALID_REQUEST);
+#endif // defined(ENABLE_NXDN)
                     break;
 
                 default:
@@ -922,6 +966,7 @@ void SerialPort::getStatus()
 
     reply[6U] = 0U;
 
+#if defined(ENABLE_DMR)
     if (m_dmrEnable) {
 #if defined(DUPLEX)
         if (m_duplex) {
@@ -934,23 +979,35 @@ void SerialPort::getStatus()
 #else
         reply[7U] = 10U;
         reply[8U] = dmrDMOTX.getSpace();
-#endif
+#endif // defined(DUPLEX)
     } else {
         reply[7U] = 0U;
         reply[8U] = 0U;
     }
+#else
+    reply[7U] = 0U;
+    reply[8U] = 0U;
+#endif // defined(ENABLE_DMR)
 
     reply[9U] = 0U;
 
+#if defined(ENABLE_P25)
     if (m_p25Enable)
         reply[10U] = p25TX.getSpace();
     else
         reply[10U] = 0U;
+#else        
+    reply[10U] = 0U;
+#endif // defined(ENABLE_P25)
 
+#if defined(ENABLE_NXDN)
     if (m_nxdnEnable)
         reply[11U] = nxdnTX.getSpace();
     else
         reply[11U] = 0U;
+#else        
+    reply[11U] = 0U;
+#endif // defined(ENABLE_NXDN)
 
     writeInt(1U, reply, 12);
 }
@@ -1089,20 +1146,28 @@ uint8_t SerialPort::setConfig(const uint8_t* data, uint8_t length)
 
     io.setDeviations(dmrTXLevel, p25TXLevel, nxdnTXLevel);
 
+#if defined(ENABLE_P25)
     p25TX.setPreambleCount(fdmaPreamble);
+#endif // defined(ENABLE_P25)
+#if defined(ENABLE_DMR)
     dmrDMOTX.setPreambleCount(fdmaPreamble);
+#endif // defined(ENABLE_DMR)
     //nxdnTX.setPreambleCount(fdmaPreamble);
 
+#if defined(ENABLE_P25)
     p25RX.setNAC(nac);
+#endif // defined(ENABLE_P25)
 
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
     dmrTX.setColorCode(colorCode);
     dmrRX.setColorCode(colorCode);
     dmrRX.setRxDelay(dmrRxDelay);
     dmrIdleRX.setColorCode(colorCode);
-#endif
+#endif // defined(DUPLEX)
 
     dmrDMORX.setColorCode(colorCode);
+#endif // defined(ENABLE_DMR)
 
     if (m_modemState != STATE_IDLE && isCalState(m_modemState)) {
         io.updateCal(calRelativeState(m_modemState));
@@ -1149,116 +1214,176 @@ void SerialPort::setMode(DVM_STATE modemState)
     switch (modemState) {
     case STATE_DMR:
         DEBUG1("SerialPort: setMode(): mode set to DMR");
+#if defined(ENABLE_P25)        
         p25RX.reset();
+#endif // defined(ENABLE_P25)
+#if defined(ENABLE_NXDN)
         nxdnRX.reset();
+#endif // defined(ENABLE_NXDN)
         cwIdTX.reset();
         break;
     case STATE_P25:
         DEBUG1("SerialPort: setMode(): mode set to P25");
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
         dmrIdleRX.reset();
         dmrRX.reset();
-#endif
+#endif // defined(DUPLEX)
         dmrDMORX.reset();
+#endif // defined(ENABLE_DMR)
+#if defined(ENABLE_NXDN)
         nxdnRX.reset();
+#endif // defined(ENABLE_NXDN)
         cwIdTX.reset();
         break;
     case STATE_NXDN:
         DEBUG1("SerialPort: setMode(): mode set to NXDN");
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
         dmrIdleRX.reset();
         dmrRX.reset();
-#endif
+#endif // defined(DUPLEX)
         dmrDMORX.reset();
+#endif // defined(ENABLE_DMR)
+#if defined(ENABLE_P25)        
         p25RX.reset();
+#endif // defined(ENABLE_P25)
         cwIdTX.reset();
         break;
     case STATE_DMR_CAL:
         DEBUG1("SerialPort: setMode(): mode set to DMR Calibrate");
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
         dmrIdleRX.reset();
         dmrRX.reset();
-#endif
+#endif // defined(DUPLEX)
         dmrDMORX.reset();
+#endif // defined(ENABLE_DMR)
+#if defined(ENABLE_P25)        
         p25RX.reset();
+#endif // defined(ENABLE_P25)
+#if defined(ENABLE_NXDN)
         nxdnRX.reset();
+#endif // defined(ENABLE_NXDN)
         cwIdTX.reset();
         break;
     case STATE_P25_CAL:
         DEBUG1("SerialPort: setMode(): mode set to P25 Calibrate");
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
         dmrIdleRX.reset();
         dmrRX.reset();
-#endif
+#endif // defined(DUPLEX)
         dmrDMORX.reset();
+#endif // defined(ENABLE_DMR)
+#if defined(ENABLE_P25)        
         p25RX.reset();
+#endif // defined(ENABLE_P25)
+#if defined(ENABLE_NXDN)
         nxdnRX.reset();
+#endif // defined(ENABLE_NXDN)
         cwIdTX.reset();
         break;
     case STATE_NXDN_CAL:
         DEBUG1("SerialPort: setMode(): mode set to NXDN Calibrate");
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
         dmrIdleRX.reset();
         dmrRX.reset();
-#endif
+#endif // defined(DUPLEX)
         dmrDMORX.reset();
+#endif // defined(ENABLE_DMR)
+#if defined(ENABLE_P25)        
         p25RX.reset();
+#endif // defined(ENABLE_P25)
+#if defined(ENABLE_NXDN)
         nxdnRX.reset();
+#endif // defined(ENABLE_NXDN)
         cwIdTX.reset();
         break;
     case STATE_RSSI_CAL:
         DEBUG1("SerialPort: setMode(): mode set to RSSI Calibrate");
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
         dmrIdleRX.reset();
         dmrRX.reset();
-#endif
+#endif // defined(DUPLEX)
         dmrDMORX.reset();
+#endif // defined(ENABLE_DMR)
+#if defined(ENABLE_P25)        
         p25RX.reset();
+#endif // defined(ENABLE_P25)
+#if defined(ENABLE_NXDN)
         nxdnRX.reset();
+#endif // defined(ENABLE_NXDN)
         cwIdTX.reset();
         break;
     case STATE_DMR_LF_CAL:
         DEBUG1("SerialPort: setMode(): mode set to DMR 80Hz Calibrate");
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
         dmrIdleRX.reset();
         dmrRX.reset();
-#endif
+#endif // defined(DUPLEX)
         dmrDMORX.reset();
+#endif // defined(ENABLE_DMR)
+#if defined(ENABLE_P25)        
         p25RX.reset();
+#endif // defined(ENABLE_P25)
+#if defined(ENABLE_NXDN)
         nxdnRX.reset();
+#endif // defined(ENABLE_NXDN)
         cwIdTX.reset();
         break;
     case STATE_DMR_CAL_1K:
         DEBUG1("SerialPort: setMode(): mode set to DMR BS 1031Hz Calibrate");
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
         dmrIdleRX.reset();
         dmrRX.reset();
-#endif
+#endif // defined(DUPLEX)
         dmrDMORX.reset();
+#endif // defined(ENABLE_DMR)
+#if defined(ENABLE_P25)        
         p25RX.reset();
+#endif // defined(ENABLE_P25)
+#if defined(ENABLE_NXDN)
         nxdnRX.reset();
+#endif // defined(ENABLE_NXDN)
         cwIdTX.reset();
         break;
     case STATE_DMR_DMO_CAL_1K:
         DEBUG1("SerialPort: setMode(): mode set to DMR MS 1031Hz Calibrate");
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
         dmrIdleRX.reset();
         dmrRX.reset();
-#endif
+#endif // defined(DUPLEX)
         dmrDMORX.reset();
+#endif // defined(ENABLE_DMR)
+#if defined(ENABLE_P25)        
         p25RX.reset();
+#endif // defined(ENABLE_P25)
+#if defined(ENABLE_NXDN)
         nxdnRX.reset();
+#endif // defined(ENABLE_NXDN)
         cwIdTX.reset();
         break;
     case STATE_P25_CAL_1K:
         DEBUG1("SerialPort: setMode(): mode set to P25 1011Hz Calibrate");
+#if defined(ENABLE_DMR)
 #if defined(DUPLEX)
         dmrIdleRX.reset();
         dmrRX.reset();
-#endif
+#endif // defined(DUPLEX)
         dmrDMORX.reset();
+#endif // defined(ENABLE_DMR)
+#if defined(ENABLE_P25)        
         p25RX.reset();
+#endif // defined(ENABLE_P25)
+#if defined(ENABLE_NXDN)
         nxdnRX.reset();
+#endif // defined(ENABLE_NXDN)
         cwIdTX.reset();
         break;
     default:
diff --git a/dmr/CalDMR.cpp b/dmr/CalDMR.cpp
index 79d9152..4d09b0c 100644
--- a/dmr/CalDMR.cpp
+++ b/dmr/CalDMR.cpp
@@ -34,6 +34,8 @@
 
 using namespace dmr;
 
+#if defined(ENABLE_DMR)
+
 // ---------------------------------------------------------------------------
 //  Constants
 // ---------------------------------------------------------------------------
@@ -289,3 +291,5 @@ uint8_t CalDMR::write(const uint8_t* data, uint8_t length)
 
     return RSN_OK;
 }
+
+#endif // defined(ENABLE_DMR)
\ No newline at end of file
diff --git a/dmr/CalDMR.h b/dmr/CalDMR.h
index 5d0b097..2b17f05 100644
--- a/dmr/CalDMR.h
+++ b/dmr/CalDMR.h
@@ -35,6 +35,8 @@
 #include "Defines.h"
 #include "dmr/DMRDefines.h"
 
+#if defined(ENABLE_DMR)
+
 namespace dmr
 {
     // ---------------------------------------------------------------------------
@@ -87,4 +89,6 @@ namespace dmr
     };
 } // namespace dmr
 
+#endif // defined(ENABLE_DMR)
+
 #endif // __CAL_DMR_H__
diff --git a/dmr/DMRDMORX.cpp b/dmr/DMRDMORX.cpp
index 1f18862..23e2de5 100644
--- a/dmr/DMRDMORX.cpp
+++ b/dmr/DMRDMORX.cpp
@@ -36,6 +36,8 @@
 
 using namespace dmr;
 
+#if defined(ENABLE_DMR)
+
 // ---------------------------------------------------------------------------
 //  Constants
 // ---------------------------------------------------------------------------
@@ -380,3 +382,4 @@ void DMRDMORX::writeRSSIData(uint8_t* frame)
 #endif
 }
 
+#endif // defined(ENABLE_DMR)
diff --git a/dmr/DMRDMORX.h b/dmr/DMRDMORX.h
index 0fae4e1..b325157 100644
--- a/dmr/DMRDMORX.h
+++ b/dmr/DMRDMORX.h
@@ -35,6 +35,8 @@
 #include "Defines.h"
 #include "dmr/DMRDefines.h"
 
+#if defined(ENABLE_DMR)
+
 namespace dmr
 {
     // ---------------------------------------------------------------------------
@@ -100,4 +102,6 @@ namespace dmr
     };
 } // namespace dmr
 
+#endif // defined(ENABLE_DMR)
+
 #endif // __DMR_DMO_RX_H__
diff --git a/dmr/DMRDMOTX.cpp b/dmr/DMRDMOTX.cpp
index ffd42e7..08b50fe 100644
--- a/dmr/DMRDMOTX.cpp
+++ b/dmr/DMRDMOTX.cpp
@@ -35,6 +35,8 @@
 
 using namespace dmr;
 
+#if defined(ENABLE_DMR)
+
 // ---------------------------------------------------------------------------
 //  Constants
 // ---------------------------------------------------------------------------
@@ -175,3 +177,5 @@ void DMRDMOTX::writeByte(uint8_t c)
         io.write(&bit, 1);
     }
 }
+
+#endif // defined(ENABLE_DMR)
\ No newline at end of file
diff --git a/dmr/DMRDMOTX.h b/dmr/DMRDMOTX.h
index cedeb2a..6ad15c0 100644
--- a/dmr/DMRDMOTX.h
+++ b/dmr/DMRDMOTX.h
@@ -37,6 +37,8 @@
 #include "dmr/DMRDefines.h"
 #include "SerialBuffer.h"
 
+#if defined(ENABLE_DMR)
+
 namespace dmr
 {
     // ---------------------------------------------------------------------------
@@ -82,4 +84,6 @@ namespace dmr
     };
 } // namespace dmr
 
+#endif // defined(ENABLE_DMR)
+
 #endif // __DMR_DMO_TX_H__
diff --git a/dmr/DMRIdleRX.cpp b/dmr/DMRIdleRX.cpp
index 29be454..8f3a357 100644
--- a/dmr/DMRIdleRX.cpp
+++ b/dmr/DMRIdleRX.cpp
@@ -35,7 +35,7 @@
 
 using namespace dmr;
 
-#if defined(DUPLEX)
+#if defined(ENABLE_DMR) && defined(DUPLEX)
 
 // ---------------------------------------------------------------------------
 //  Constants
@@ -185,4 +185,4 @@ void DMRIdleRX::bitsToBytes(uint16_t start, uint8_t count, uint8_t* buffer)
   }
 }
 
-#endif // DUPLEX
+#endif // defined(ENABLE_DMR) && defined(DUPLEX)
diff --git a/dmr/DMRIdleRX.h b/dmr/DMRIdleRX.h
index 3031bb6..6459f2d 100644
--- a/dmr/DMRIdleRX.h
+++ b/dmr/DMRIdleRX.h
@@ -34,7 +34,7 @@
 #include "Defines.h"
 #include "dmr/DMRDefines.h"
 
-#if defined(DUPLEX)
+#if defined(ENABLE_DMR) && defined(DUPLEX)
 
 namespace dmr
 {
@@ -77,6 +77,6 @@ namespace dmr
     };
 } // namespace dmr
 
-#endif // DUPLEX
+#endif // defined(ENABLE_DMR) && defined(DUPLEX)
 
 #endif // __DMR_IDLE_RX_H__
diff --git a/dmr/DMRRX.cpp b/dmr/DMRRX.cpp
index 04a0ad0..384882f 100644
--- a/dmr/DMRRX.cpp
+++ b/dmr/DMRRX.cpp
@@ -34,7 +34,7 @@
 
 using namespace dmr;
 
-#if defined(DUPLEX)
+#if defined(ENABLE_DMR) && defined(DUPLEX)
 
 // ---------------------------------------------------------------------------
 //  Public Class Members
@@ -106,4 +106,4 @@ void DMRRX::setRxDelay(uint8_t delay)
     m_slot2RX.setRxDelay(delay);
 }
 
-#endif // DUPLEX
+#endif // defined(ENABLE_DMR) && defined(DUPLEX)
diff --git a/dmr/DMRRX.h b/dmr/DMRRX.h
index 326a7fc..a659302 100644
--- a/dmr/DMRRX.h
+++ b/dmr/DMRRX.h
@@ -35,7 +35,7 @@
 #include "Defines.h"
 #include "dmr/DMRSlotRX.h"
 
-#if defined(DUPLEX)
+#if defined(ENABLE_DMR) && defined(DUPLEX)
 
 namespace dmr
 {
@@ -66,6 +66,6 @@ namespace dmr
     };
 } // namespace dmr
 
-#endif // DUPLEX
+#endif // defined(ENABLE_DMR) && defined(DUPLEX)
 
 #endif // __DMR_RX_H__
diff --git a/dmr/DMRSlotRX.cpp b/dmr/DMRSlotRX.cpp
index 6e173ac..74c8147 100644
--- a/dmr/DMRSlotRX.cpp
+++ b/dmr/DMRSlotRX.cpp
@@ -36,7 +36,7 @@
 
 using namespace dmr;
 
-#if defined(DUPLEX)
+#if defined(ENABLE_DMR) && defined(DUPLEX)
 
 // ---------------------------------------------------------------------------
 //  Constants
@@ -417,4 +417,4 @@ void DMRSlotRX::writeRSSIData(uint8_t* frame)
 #endif
 }
 
-#endif // DUPLEX
+#endif // defined(ENABLE_DMR) && defined(DUPLEX)
diff --git a/dmr/DMRSlotRX.h b/dmr/DMRSlotRX.h
index 6d7fa0d..476ff14 100644
--- a/dmr/DMRSlotRX.h
+++ b/dmr/DMRSlotRX.h
@@ -35,7 +35,7 @@
 #include "Defines.h"
 #include "dmr/DMRDefines.h"
 
-#if defined(DUPLEX)
+#if defined(ENABLE_DMR) && defined(DUPLEX)
 
 namespace dmr
 {
@@ -110,6 +110,6 @@ namespace dmr
     };
 } // namespace dmr
 
-#endif // DUPLEX
+#endif // defined(ENABLE_DMR) && defined(DUPLEX)
 
 #endif // __DMR_SLOT_RX_H__
diff --git a/dmr/DMRSlotType.cpp b/dmr/DMRSlotType.cpp
index 1c1b29f..ea87622 100644
--- a/dmr/DMRSlotType.cpp
+++ b/dmr/DMRSlotType.cpp
@@ -32,6 +32,8 @@
 
 using namespace dmr;
 
+#if defined(ENABLE_DMR)
+
 // ---------------------------------------------------------------------------
 //  Constants
 // ---------------------------------------------------------------------------
@@ -334,3 +336,5 @@ uint32_t DMRSlotType::getSyndrome1987(uint32_t pattern) const
 
     return pattern;
 }
+
+#endif // defined(ENABLE_DMR)
\ No newline at end of file
diff --git a/dmr/DMRSlotType.h b/dmr/DMRSlotType.h
index f802980..1e2ff5f 100644
--- a/dmr/DMRSlotType.h
+++ b/dmr/DMRSlotType.h
@@ -32,6 +32,8 @@
 
 #include "Defines.h"
 
+#if defined(ENABLE_DMR)
+
 namespace dmr
 {
     // ---------------------------------------------------------------------------
@@ -57,4 +59,6 @@ namespace dmr
     };
 } // namespace dmr
 
+#endif // defined(ENABLE_DMR)
+
 #endif // __DMR_SLOT_TYPE_H__
diff --git a/dmr/DMRTX.cpp b/dmr/DMRTX.cpp
index 81c4d57..a35f6da 100644
--- a/dmr/DMRTX.cpp
+++ b/dmr/DMRTX.cpp
@@ -35,6 +35,8 @@
 
 using namespace dmr;
 
+#if defined(ENABLE_DMR)
+
 // ---------------------------------------------------------------------------
 //  Constants
 // ---------------------------------------------------------------------------
@@ -523,3 +525,5 @@ void DMRTX::writeByte(uint8_t c, uint8_t control)
         io.write(&bit, 1, &controlToWrite);
     }
 }
+
+#endif // defined(ENABLE_DMR)
diff --git a/dmr/DMRTX.h b/dmr/DMRTX.h
index baf6d71..3be1ba2 100644
--- a/dmr/DMRTX.h
+++ b/dmr/DMRTX.h
@@ -37,6 +37,8 @@
 #include "dmr/DMRDefines.h"
 #include "SerialBuffer.h"
 
+#if defined(ENABLE_DMR)
+
 namespace dmr
 {
     // ---------------------------------------------------------------------------
@@ -135,4 +137,6 @@ namespace dmr
     };
 } // namespace dmr
 
+#endif // defined(ENABLE_DMR)
+
 #endif // __DMR_TX_H__
diff --git a/nxdn/CalNXDN.cpp b/nxdn/CalNXDN.cpp
index 7ea852d..846c2c8 100644
--- a/nxdn/CalNXDN.cpp
+++ b/nxdn/CalNXDN.cpp
@@ -33,6 +33,8 @@
 
 using namespace nxdn;
 
+#if defined(ENABLE_NXDN)
+
 // ---------------------------------------------------------------------------
 //  Constants
 // ---------------------------------------------------------------------------
@@ -138,3 +140,5 @@ uint8_t CalNXDN::write(const uint8_t* data, uint16_t length)
 
     return RSN_OK;
 }
+
+#endif // defined(ENABLE_NXDN)
\ No newline at end of file
diff --git a/nxdn/CalNXDN.h b/nxdn/CalNXDN.h
index ecb45cc..bddb765 100644
--- a/nxdn/CalNXDN.h
+++ b/nxdn/CalNXDN.h
@@ -35,6 +35,8 @@
 #include "Defines.h"
 #include "nxdn/NXDNDefines.h"
 
+#if defined(ENABLE_NXDN)
+
 namespace nxdn
 {
     // ---------------------------------------------------------------------------
@@ -70,4 +72,6 @@ namespace nxdn
     };
 } // namespace nxdn
 
+#endif // defined(ENABLE_NXDN)
+
 #endif // __CAL_NXDN_H__
diff --git a/nxdn/NXDNRX.cpp b/nxdn/NXDNRX.cpp
index e0c8550..51bf8bf 100644
--- a/nxdn/NXDNRX.cpp
+++ b/nxdn/NXDNRX.cpp
@@ -34,6 +34,8 @@
 
 using namespace nxdn;
 
+#if defined(ENABLE_NXDN)
+
 // ---------------------------------------------------------------------------
 //  Constants
 // ---------------------------------------------------------------------------
@@ -196,3 +198,5 @@ bool NXDNRX::correlateSync(bool first)
 
     return false;
 }
+
+#endif // defined(ENABLE_NXDN)
\ No newline at end of file
diff --git a/nxdn/NXDNRX.h b/nxdn/NXDNRX.h
index 56669d5..ec13604 100644
--- a/nxdn/NXDNRX.h
+++ b/nxdn/NXDNRX.h
@@ -34,6 +34,7 @@
 #include "Defines.h"
 #include "nxdn/NXDNDefines.h"
 
+#if defined(ENABLE_NXDN)
 namespace nxdn
 {
     // ---------------------------------------------------------------------------
@@ -81,5 +82,6 @@ namespace nxdn
         bool correlateSync(bool first = false);
     };
 } // namespace nxdn
+#endif // defined(ENABLE_NXDN)
 
 #endif // __NXDN_RX_H__
diff --git a/nxdn/NXDNTX.cpp b/nxdn/NXDNTX.cpp
index 5aad090..c641583 100644
--- a/nxdn/NXDNTX.cpp
+++ b/nxdn/NXDNTX.cpp
@@ -35,6 +35,8 @@
 
 using namespace nxdn;
 
+#if defined(ENABLE_NXDN)
+
 // ---------------------------------------------------------------------------
 //  Public Class Members
 // ---------------------------------------------------------------------------
@@ -241,3 +243,5 @@ void NXDNTX::writeSilence()
         io.write(&bit, 1);
     }
 }
+
+#endif // defined(ENABLE_NXDN)
\ No newline at end of file
diff --git a/nxdn/NXDNTX.h b/nxdn/NXDNTX.h
index f869afe..7058868 100644
--- a/nxdn/NXDNTX.h
+++ b/nxdn/NXDNTX.h
@@ -35,6 +35,8 @@
 #include "Defines.h"
 #include "SerialBuffer.h"
 
+#if defined(ENABLE_NXDN)
+
 namespace nxdn
 {
     // ---------------------------------------------------------------------------
@@ -100,4 +102,6 @@ namespace nxdn
     };
 } // namespace nxdn
 
+#endif // defined(ENABLE_NXDN)
+
 #endif // __NXDN_TX_H__
diff --git a/p25/CalP25.cpp b/p25/CalP25.cpp
index 1ec050c..5190548 100644
--- a/p25/CalP25.cpp
+++ b/p25/CalP25.cpp
@@ -32,6 +32,8 @@
 
 using namespace p25;
 
+#if defined(ENABLE_P25)
+
 // ---------------------------------------------------------------------------
 //  Constants
 // ---------------------------------------------------------------------------
@@ -143,3 +145,5 @@ uint8_t CalP25::write(const uint8_t* data, uint8_t length)
 
     return RSN_OK;
 }
+
+#endif // defined(ENABLE_P25)
\ No newline at end of file
diff --git a/p25/CalP25.h b/p25/CalP25.h
index f8113e6..6ce72cf 100644
--- a/p25/CalP25.h
+++ b/p25/CalP25.h
@@ -33,6 +33,8 @@
 #include "Defines.h"
 #include "p25/P25Defines.h"
 
+#if defined(ENABLE_P25)
+
 namespace p25
 {
     // ---------------------------------------------------------------------------
@@ -67,4 +69,6 @@ namespace p25
     };
 } // namespace p25
 
+#endif // defined(ENABLE_P25)
+
 #endif // __CAL_P25_H__
diff --git a/p25/P25RX.cpp b/p25/P25RX.cpp
index b4f822b..4631205 100644
--- a/p25/P25RX.cpp
+++ b/p25/P25RX.cpp
@@ -35,6 +35,8 @@
 
 using namespace p25;
 
+#if defined(ENABLE_P25)
+
 // ---------------------------------------------------------------------------
 //  Constants
 // ---------------------------------------------------------------------------
@@ -461,3 +463,5 @@ bool P25RX::decodeNid()
 
     return false;
 }
+
+#endif // defined(ENABLE_P25)
diff --git a/p25/P25RX.h b/p25/P25RX.h
index 3029b89..d9f9eb8 100644
--- a/p25/P25RX.h
+++ b/p25/P25RX.h
@@ -35,6 +35,8 @@
 #include "Defines.h"
 #include "p25/P25Defines.h"
 
+#if defined(ENABLE_P25)
+
 namespace p25
 {
     // ---------------------------------------------------------------------------
@@ -98,4 +100,6 @@ namespace p25
     };
 } // namespace p25
 
+#endif // defined(ENABLE_P25)
+
 #endif // __P25_RX_H__
diff --git a/p25/P25TX.cpp b/p25/P25TX.cpp
index 29eeec4..cc564fa 100644
--- a/p25/P25TX.cpp
+++ b/p25/P25TX.cpp
@@ -35,6 +35,8 @@
 
 using namespace p25;
 
+#if defined(ENABLE_P25)
+
 // ---------------------------------------------------------------------------
 //  Public Class Members
 // ---------------------------------------------------------------------------
@@ -270,3 +272,5 @@ void P25TX::writeSilence()
         io.write(&bit, 1);
     }
 }
+
+#endif // defined(ENABLE_P25)
diff --git a/p25/P25TX.h b/p25/P25TX.h
index 667e184..c3f1c31 100644
--- a/p25/P25TX.h
+++ b/p25/P25TX.h
@@ -35,6 +35,8 @@
 #include "Defines.h"
 #include "SerialBuffer.h"
 
+#if defined(ENABLE_P25)
+
 namespace p25
 {
     // ---------------------------------------------------------------------------
@@ -103,4 +105,6 @@ namespace p25
     };
 } // namespace p25
 
+#endif // defined(ENABLE_P25)
+
 #endif // __P25_TX_H__