diff --git a/src/cdmrmmdvmprotocol.cpp b/src/cdmrmmdvmprotocol.cpp
index 3e8868e..0e67704 100644
--- a/src/cdmrmmdvmprotocol.cpp
+++ b/src/cdmrmmdvmprotocol.cpp
@@ -511,7 +511,7 @@ bool CDmrmmdvmProtocol::IsValidKeepAlivePacket(const CBuffer &Buffer, CCallsign
     {
         uint32 uiRptrId = MAKEDWORD(MAKEWORD(Buffer.data()[10],Buffer.data()[9]),MAKEWORD(Buffer.data()[8],Buffer.data()[7]));
         callsign->SetDmrid(uiRptrId, true);
-        callsign->SetModule('B');
+        callsign->SetModule(MMDVM_MODULE_ID);
         valid = callsign->IsValid();
     }
     return valid;
@@ -526,7 +526,7 @@ bool CDmrmmdvmProtocol::IsValidConnectPacket(const CBuffer &Buffer, CCallsign *c
     {
         uint32 uiRptrId = MAKEDWORD(MAKEWORD(Buffer.data()[7],Buffer.data()[6]),MAKEWORD(Buffer.data()[5],Buffer.data()[4]));
         callsign->SetDmrid(uiRptrId, true);
-        callsign->SetModule('B');
+        callsign->SetModule(MMDVM_MODULE_ID);
         valid = callsign->IsValid();
         if ( !valid)
         {
@@ -545,7 +545,7 @@ bool CDmrmmdvmProtocol::IsValidAuthenticationPacket(const CBuffer &Buffer, CCall
     {
         uint32 uiRptrId = MAKEDWORD(MAKEWORD(Buffer.data()[7],Buffer.data()[6]),MAKEWORD(Buffer.data()[5],Buffer.data()[4]));
         callsign->SetDmrid(uiRptrId, true);
-        callsign->SetModule('B');
+        callsign->SetModule(MMDVM_MODULE_ID);
         valid = callsign->IsValid();
     }
     return valid;
@@ -560,7 +560,7 @@ bool CDmrmmdvmProtocol::IsValidDisconnectPacket(const CBuffer &Buffer, CCallsign
     {
         uint32 uiRptrId = MAKEDWORD(MAKEWORD(Buffer.data()[7],Buffer.data()[6]),MAKEWORD(Buffer.data()[5],Buffer.data()[4]));
         callsign->SetDmrid(uiRptrId, true);
-        callsign->SetModule('B');
+        callsign->SetModule(MMDVM_MODULE_ID);
         valid = callsign->IsValid();
     }
     return valid;
@@ -575,7 +575,7 @@ bool CDmrmmdvmProtocol::IsValidConfigPacket(const CBuffer &Buffer, CCallsign *ca
     {
         uint32 uiRptrId = MAKEDWORD(MAKEWORD(Buffer.data()[7],Buffer.data()[6]),MAKEWORD(Buffer.data()[5],Buffer.data()[4]));
         callsign->SetDmrid(uiRptrId, true);
-        callsign->SetModule('B');
+        callsign->SetModule(MMDVM_MODULE_ID);
         valid = callsign->IsValid();
     }
     return valid;
@@ -590,7 +590,7 @@ bool CDmrmmdvmProtocol::IsValidOptionPacket(const CBuffer &Buffer, CCallsign *ca
     {
         uint32 uiRptrId = MAKEDWORD(MAKEWORD(Buffer.data()[7],Buffer.data()[6]),MAKEWORD(Buffer.data()[5],Buffer.data()[4]));
         callsign->SetDmrid(uiRptrId, true);
-        callsign->SetModule('B');
+        callsign->SetModule(MMDVM_MODULE_ID);
         valid = callsign->IsValid();
     }
     return valid;
@@ -673,7 +673,7 @@ bool CDmrmmdvmProtocol::IsValidDvHeaderPacket(const CBuffer &Buffer, CDvHeaderPa
                 // build DVHeader
                 CCallsign csMY =  CCallsign("", uiSrcId);
                 CCallsign rpt1 = CCallsign("", uiRptrId);
-                rpt1.SetModule('B');
+                rpt1.SetModule(MMDVM_MODULE_ID);
                 CCallsign rpt2 = m_ReflectorCallsign;
                 rpt2.SetModule(DmrDstIdToModule(uiDstId));
                 
diff --git a/src/cdmrmmdvmprotocol.h b/src/cdmrmmdvmprotocol.h
index 2f221c5..52b5e64 100644
--- a/src/cdmrmmdvmprotocol.h
+++ b/src/cdmrmmdvmprotocol.h
@@ -43,6 +43,9 @@
 #define MMDVM_SLOTTYPE_HEADER        1
 #define MMDVM_SLOTTYPE_TERMINATOR    2
 
+// DMRMMDVM Module ID
+#define MMDVM_MODULE_ID             'B'
+
 ////////////////////////////////////////////////////////////////////////////////////////
 // class
 
diff --git a/src/cdmrplusprotocol.cpp b/src/cdmrplusprotocol.cpp
index fb4f270..76bfd43 100644
--- a/src/cdmrplusprotocol.cpp
+++ b/src/cdmrplusprotocol.cpp
@@ -414,7 +414,7 @@ bool CDmrplusProtocol::IsValidConnectPacket(const CBuffer &Buffer, CCallsign *ca
         sz[8] = 0;
         uint32 dmrid = atoi(sz);
         callsign->SetDmrid(dmrid, true);
-        callsign->SetModule('B');
+        callsign->SetModule(DMRPLUS_MODULE_ID);
         ::memcpy(sz, &Buffer.data()[8], 4);
         sz[4] = 0;
         *reflectormodule = DmrDstIdToModule(atoi(sz));
@@ -437,7 +437,7 @@ bool CDmrplusProtocol::IsValidDisconnectPacket(const CBuffer &Buffer, CCallsign
         sz[8] = 0;
         uint32 dmrid = atoi(sz);
         callsign->SetDmrid(dmrid, true);
-        callsign->SetModule('B');
+        callsign->SetModule(DMRPLUS_MODULE_ID);
         *reflectormodule = Buffer.data()[11] - '0' + 'A';
         valid = (callsign->IsValid() && std::isupper(*reflectormodule));
     }
@@ -467,7 +467,7 @@ bool CDmrplusProtocol::IsValidDvHeaderPacket(const CIp &Ip, const CBuffer &Buffe
             // build DVHeader
             CCallsign csMY =  CCallsign("", uiSrcId);
             CCallsign rpt1 = CCallsign("", uiSrcId);
-            rpt1.SetModule('B');
+            rpt1.SetModule(DMRPLUS_MODULE_ID);
             CCallsign rpt2 = m_ReflectorCallsign;
             rpt2.SetModule(DmrDstIdToModule(uiDstId));
             uint32 uiStreamId = IpToStreamId(Ip);
diff --git a/src/cdmrplusprotocol.h b/src/cdmrplusprotocol.h
index 430f741..e142a72 100644
--- a/src/cdmrplusprotocol.h
+++ b/src/cdmrplusprotocol.h
@@ -34,6 +34,9 @@
 ////////////////////////////////////////////////////////////////////////////////////////
 // define
 
+// DMR Plus Module ID
+#define DMRPLUS_MODULE_ID       'B'
+
 ////////////////////////////////////////////////////////////////////////////////////////
 // class