1 files changed, 1 insertions, 1 deletions
diff --git a/tdd.c b/tdd.c
index e2a6cc839..a3664e82e 100755
--- a/tdd.c
+++ b/tdd.c
@@ -233,7 +233,7 @@ static inline float tdd_getcarrier(float *cr, float *ci, int bit)
 	PUT_TDD_STOP;	/* Stop bit */ \
 } while(0);	
 
-int tdd_generate(struct tdd_state *tdd, unsigned char *buf, char *str)
+int tdd_generate(struct tdd_state *tdd, unsigned char *buf, const char *str)
 {
 	int bytes=0;
 	int i,x;