diff --git a/drivers/net/ppp_synctty.c b/drivers/net/ppp_synctty.c
index 33cb825..33255fe 100644
--- a/drivers/net/ppp_synctty.c
+++ b/drivers/net/ppp_synctty.c
@@ -108,7 +108,7 @@
 ppp_print_hex (register __u8 * out, const __u8 * in, int count)
 {
 	register __u8 next_ch;
-	static char hex[] = "0123456789ABCDEF";
+	static const char hex[] = "0123456789ABCDEF";
 
 	while (count-- > 0) {
 		next_ch = *in++;