diff --git a/drivers/isdn/hysdn/hycapi.c b/drivers/isdn/hysdn/hycapi.c
index d3999a8e9f88cb55516cde292fd04af447ae32b5..53f6ad1235db652d02fb62e8821db4a297535941 100644
--- a/drivers/isdn/hysdn/hycapi.c
+++ b/drivers/isdn/hysdn/hycapi.c
@@ -462,11 +462,11 @@ static int hycapi_read_proc(char *page, char **start, off_t off,
 		default: s = "???"; break;
 	}
 	len += sprintf(page+len, "%-16s %s\n", "type", s);
-	if ((s = cinfo->version[VER_DRIVER]) != 0)
+	if ((s = cinfo->version[VER_DRIVER]) != NULL)
 		len += sprintf(page+len, "%-16s %s\n", "ver_driver", s);
-	if ((s = cinfo->version[VER_CARDTYPE]) != 0)
+	if ((s = cinfo->version[VER_CARDTYPE]) != NULL)
 		len += sprintf(page+len, "%-16s %s\n", "ver_cardtype", s);
-	if ((s = cinfo->version[VER_SERIAL]) != 0)
+	if ((s = cinfo->version[VER_SERIAL]) != NULL)
 		len += sprintf(page+len, "%-16s %s\n", "ver_serial", s);
     
 	len += sprintf(page+len, "%-16s %s\n", "cardname", cinfo->cardname);