diff --git a/libs/freetdm/src/isdn/Q931.c b/libs/freetdm/src/isdn/Q931.c
index 01966b389e..ac22d79d25 100644
--- a/libs/freetdm/src/isdn/Q931.c
+++ b/libs/freetdm/src/isdn/Q931.c
@@ -96,7 +96,7 @@ L3INT (*Q931Tx32Proc)(Q931_TrunkInfo *pTrunk,L3UCHAR *,L3INT);
 									/* callback ptr for messages to be send */
                                     /* to layer 2.                          */
 
-void (*Q931ErrorProc)(Q931_TrunkInfo *pTrunk, L3INT,L3INT,L3INT); 
+L3INT (*Q931ErrorProc)(Q931_TrunkInfo *pTrunk, L3INT,L3INT,L3INT); 
 									/* callback for error messages.         */
 
 L3ULONG (*Q931GetTimeProc) ()=NULL; /* callback for func reading time in ms */
@@ -210,8 +210,9 @@ L3INT Q931TxDummy(Q931_TrunkInfo *pTrunk, L3UCHAR * b, L3INT n)
   Description:  Dummy function for error processing
 
 *****************************************************************************/
-void Q931ErrorDummy(Q931_TrunkInfo *pTrunk,L3INT a, L3INT b, L3INT c)
+L3INT Q931ErrorDummy(Q931_TrunkInfo *pTrunk,L3INT a, L3INT b, L3INT c)
 {
+	return 0;
 }
 
 /*****************************************************************************
diff --git a/libs/freetdm/src/isdn/Q931ie.c b/libs/freetdm/src/isdn/Q931ie.c
index d9cddbb16d..28b1845ca7 100644
--- a/libs/freetdm/src/isdn/Q931ie.c
+++ b/libs/freetdm/src/isdn/Q931ie.c
@@ -1310,6 +1310,8 @@ L3USHORT Q931Uie_CRV(Q931_TrunkInfo *pTrunk, L3UCHAR *IBuf, L3UCHAR *OBuf, L3INT
     else
     {
 		/* Long CRV is not used, so we skip this */
+		/* TODO: is it right to set to 0 here? */
+		CRV = 0;
         Octet+=l;
     }
 
diff --git a/libs/freetdm/src/isdn/include/Q931.h b/libs/freetdm/src/isdn/include/Q931.h
index f320504e6a..663d18d2da 100644
--- a/libs/freetdm/src/isdn/include/Q931.h
+++ b/libs/freetdm/src/isdn/include/Q931.h
@@ -117,7 +117,7 @@
 /* warning C4189 : local variable is initialized but not referenced  TODO:  This one should not be disabled */
 /* warning C4554: '&' : check operator precedence for possible error; use parentheses to clarify precedence TODO:  This one should not be disabled */
 /* warning C4267: '=' : conversion from 'size_t' to 'unsigned char', possible loss of data TODO:  This one should not be disabled */
-#pragma warning(disable:4244 4189 4554 4267)
+#pragma warning(disable:4100 4244 4189 4554 4267)
 #endif
 
 /*****************************************************************************