diff --git a/include/serial.h b/include/serial.h
new file mode 100644
index 0000000..de29c62
--- /dev/null
+++ b/include/serial.h
@@ -0,0 +1,16 @@
+/*
+ * AsterOS Kernel
+ * Serial (COM1) diagnostics output
+ */
+
+#ifndef ASTER_SERIAL_H
+#define ASTER_SERIAL_H
+
+#include "types.h"
+
+void serial_init(void);
+int serial_is_ready(void);
+void serial_write_char(char c);
+void serial_write_string(const char *text);
+
+#endif