diff --git a/libs/freetdm/src/ftdm_io.c b/libs/freetdm/src/ftdm_io.c
index e13d0196b8..2fa795344a 100644
--- a/libs/freetdm/src/ftdm_io.c
+++ b/libs/freetdm/src/ftdm_io.c
@@ -2715,7 +2715,8 @@ FT_DECLARE(ftdm_status_t) ftdm_channel_command(ftdm_channel_t *ftdmchan, ftdm_co
 				close(ftdmchan->fds[FTDM_READ_TRACE_INDEX]);
 				ftdmchan->fds[FTDM_READ_TRACE_INDEX] = -1;
 			}
-			if ((ftdmchan->fds[FTDM_READ_TRACE_INDEX] = open(path, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR)) > -1) {
+			if ((ftdmchan->fds[FTDM_READ_TRACE_INDEX] = open(path, O_WRONLY | O_CREAT | O_TRUNC 
+							| FTDM_O_BINARY, S_IRUSR | S_IWUSR)) > -1) {
 				ftdm_log(FTDM_LOG_DEBUG, "Tracing channel %u:%u input to [%s]\n", ftdmchan->span_id, ftdmchan->chan_id, path);	
 				GOTO_STATUS(done, FTDM_SUCCESS);
 			}
@@ -2731,7 +2732,8 @@ FT_DECLARE(ftdm_status_t) ftdm_channel_command(ftdm_channel_t *ftdmchan, ftdm_co
 				close(ftdmchan->fds[FTDM_WRITE_TRACE_INDEX]);
 				ftdmchan->fds[FTDM_WRITE_TRACE_INDEX] = -1;
 			}
-			if ((ftdmchan->fds[FTDM_WRITE_TRACE_INDEX] = open(path, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR)) > -1) {
+			if ((ftdmchan->fds[FTDM_WRITE_TRACE_INDEX] = open(path, O_WRONLY | O_CREAT | O_TRUNC
+							| FTDM_O_BINARY, S_IRUSR | S_IWUSR)) > -1) {
 				ftdm_log(FTDM_LOG_DEBUG, "Tracing channel %u:%u output to [%s]\n", ftdmchan->span_id, ftdmchan->chan_id, path);	
 				GOTO_STATUS(done, FTDM_SUCCESS);
 			}
@@ -3376,7 +3378,7 @@ FT_DECLARE(ftdm_status_t) ftdm_channel_queue_dtmf(ftdm_channel_t *ftdmchan, cons
 				ftdmchan->span_id, ftdmchan->chan_id, 
 				currtime.tm_year-100, currtime.tm_mon+1, currtime.tm_mday,
 				currtime.tm_hour, currtime.tm_min, currtime.tm_sec, ftdmchan->native_codec == FTDM_CODEC_ULAW ? "ulaw" : ftdmchan->native_codec == FTDM_CODEC_ALAW ? "alaw" : "sln");
-		ftdmchan->dtmfdbg.file = fopen(dfile, "w");	
+		ftdmchan->dtmfdbg.file = fopen(dfile, "wb");	
 		if (!ftdmchan->dtmfdbg.file) {
 			ftdm_log_chan(ftdmchan, FTDM_LOG_ERROR, "failed to open debug dtmf file %s\n", dfile);
 		} else {
diff --git a/libs/freetdm/src/ftmod/ftmod_r2/ftmod_r2.c b/libs/freetdm/src/ftmod/ftmod_r2/ftmod_r2.c
index 6bec6b0cf7..1549833571 100644
--- a/libs/freetdm/src/ftmod/ftmod_r2/ftmod_r2.c
+++ b/libs/freetdm/src/ftmod/ftmod_r2/ftmod_r2.c
@@ -568,14 +568,14 @@ static void dump_mf(openr2_chan_t *r2chan)
 		ftdm_log_chan(ftdmchan, FTDM_LOG_ERROR, "Dumping IO output in prefix %s\n", logname);
 		snprintf(dfile, sizeof(dfile), logname ? "%s.s%dc%d.input.alaw" : "%s/s%dc%d.input.alaw", 
 				logname ? logname : r2data->logdir, ftdmchan->span_id, ftdmchan->chan_id);
-		f = fopen(dfile, "w");
+		f = fopen(dfile, "wb");
 		ftdm_log_chan(ftdmchan, FTDM_LOG_ERROR, "Dumping IO input in file %s\n", dfile);
 		ftdm_channel_command(ftdmchan, FTDM_COMMAND_DUMP_INPUT, f);
 		fclose(f);
 
 		snprintf(dfile, sizeof(dfile), logname ? "%s.s%dc%d.output.alaw" : "%s/s%dc%d.output.alaw", 
 				logname ? logname : r2data->logdir, ftdmchan->span_id, ftdmchan->chan_id);
-		f = fopen(dfile, "w");
+		f = fopen(dfile, "wb");
 		ftdm_log_chan(ftdmchan, FTDM_LOG_ERROR, "Dumping IO output in file %s\n", dfile);
 		ftdm_channel_command(ftdmchan, FTDM_COMMAND_DUMP_OUTPUT, f);
 		fclose(f);
diff --git a/libs/freetdm/src/include/ftdm_declare.h b/libs/freetdm/src/include/ftdm_declare.h
index 4aba703f28..5c57e01a70 100644
--- a/libs/freetdm/src/include/ftdm_declare.h
+++ b/libs/freetdm/src/include/ftdm_declare.h
@@ -158,12 +158,14 @@ typedef __int64 int64_t;
 typedef __int32 int32_t;
 typedef __int16 int16_t;
 typedef __int8 int8_t;
+#define FTDM_O_BINARY O_BINARY
 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS)
 #define DELTA_EPOCH_IN_MICROSECS  11644473600000000Ui64
 #else
 #define DELTA_EPOCH_IN_MICROSECS  11644473600000000ULL
 #endif /* _MSC_VER */
 #else /* __WINDOWS__ */
+#define FTDM_O_BINARY 0
 #define FTDM_INVALID_SOCKET -1
 typedef int ftdm_socket_t;
 #include <stdio.h>