diff --git a/ChangeLog b/ChangeLog
index b229f2e1..3fe7a53a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2014-11-26  Joerg Wunsch <j.gnu@uriah.heep.sax.de>
+
+	* ser_win32.c (net_send): Properly declare argument 2 as being a
+	pointer to const data.
+
 2014-11-25  Joerg Wunsch <j.gnu@uriah.heep.sax.de>
 
 	patch #8380: adds 500k 1M 2M baud to ser_posix.c
diff --git a/ser_win32.c b/ser_win32.c
index b0c3d63c..fcaa55e6 100644
--- a/ser_win32.c
+++ b/ser_win32.c
@@ -339,11 +339,11 @@ static int ser_set_dtr_rts(union filedescriptor *fd, int is_on)
 }
 
 #ifdef HAVE_LIBWS2_32
-static int net_send(union filedescriptor *fd, unsigned char * buf, size_t buflen)
+static int net_send(union filedescriptor *fd, const unsigned char * buf, size_t buflen)
 {
 	LPVOID lpMsgBuf;
 	int rc;
-	unsigned char *p = buf;
+	const unsigned char *p = buf;
 	size_t len = buflen;
 
 	if (fd->ifd < 0) {