diff --git a/DMRIPSC.cpp b/DMRIPSC.cpp
index 8b305ed..4c66b05 100644
--- a/DMRIPSC.cpp
+++ b/DMRIPSC.cpp
@@ -245,11 +245,16 @@ bool CDMRIPSC::write(const CDMRData& data)
 	} else if (dataType == DT_VOICE) {
 		buffer[15U] |= data.getN();
 	} else {
-		if ((dataType == DT_VOICE_LC_HEADER || dataType == DT_DATA_HEADER) && data.getSeqNo() == 0U) {
+		if (dataType == DT_VOICE_LC_HEADER) {
 			m_streamId[slotIndex] = ::rand() + 1U;
 			count = 3U;
 		}
 
+		if (dataType == DT_CSBK || dataType == DT_DATA_HEADER) {
+			m_streamId[slotIndex] = ::rand() + 1U;
+			count = 1U;
+		}
+
 		buffer[15U] |= (0x20U | dataType);
 	}