diff --git a/DMRCSBK.cpp b/DMRCSBK.cpp
index de7320d..ffa7115 100644
--- a/DMRCSBK.cpp
+++ b/DMRCSBK.cpp
@@ -149,6 +149,31 @@ unsigned char CDMRCSBK::getFID() const
 	return m_FID;
 }
 
+bool CDMRCSBK::getOVCM() const
+{
+	bool bOVCM = false;
+	// Service options informations are only available in
+	// "Unit to Unit Voice Service Request CSBK" and
+	// "Unit to Unit Voice Service Answer Response CSBK"
+	if (m_CSBKO == CSBKO_UUVREQ || m_CSBKO == CSBKO_UUANSRSP)
+	{
+		bOVCM = (m_data[2U] & 0x04U) == 0x04U;
+	}
+	return bOVCM;
+}
+
+void CDMRCSBK::setOVCM(bool ovcm)
+{
+	// Set OVCM only in CSBKs having the service options information
+	if (m_CSBKO == CSBKO_UUVREQ || m_CSBKO == CSBKO_UUANSRSP)
+	{
+		if (ovcm)
+			m_data[2U] |= 0x04U;
+		else
+			m_data[2U] &= 0xFBU;
+	}
+}
+
 bool CDMRCSBK::getGI() const
 {
 	return m_GI;
diff --git a/DMRCSBK.h b/DMRCSBK.h
index 5dc62a0..914b44d 100644
--- a/DMRCSBK.h
+++ b/DMRCSBK.h
@@ -45,6 +45,10 @@ public:
 	CSBKO         getCSBKO() const;
 	unsigned char getFID() const;
 
+	// Set/Get the OVCM bit in the supported CSBKs
+	bool getOVCM() const;
+	void setOVCM(bool ovcm);
+
 	// For BS Dwn Act
 	unsigned int  getBSId() const;
 
diff --git a/DMRSlot.cpp b/DMRSlot.cpp
index 9a6d7ec..58125ad 100644
--- a/DMRSlot.cpp
+++ b/DMRSlot.cpp
@@ -423,6 +423,9 @@ bool CDMRSlot::writeModem(unsigned char *data, unsigned int len)
 			if (csbko == CSBKO_BSDWNACT)
 				return false;
 
+			// set the OVCM bit for the supported csbk
+			csbk.setOVCM(m_ovcm);
+
 			bool gi = csbk.getGI();
 			unsigned int srcId = csbk.getSrcId();
 			unsigned int dstId = csbk.getDstId();
@@ -1549,6 +1552,9 @@ void CDMRSlot::writeNetwork(const CDMRData& dmrData)
 		if (csbko == CSBKO_BSDWNACT)
 			return;
 
+		// set the OVCM bit for the supported csbk
+		csbk.setOVCM(m_ovcm);
+
 		bool gi = csbk.getGI();
 		unsigned int srcId = csbk.getSrcId();
 		unsigned int dstId = csbk.getDstId();