diff --git a/src/libmsc/a_iface.c b/src/libmsc/a_iface.c
new file mode 100644
index 0000000..1f471f9
--- /dev/null
+++ b/src/libmsc/a_iface.c
@@ -0,0 +1,45 @@
+/* A-interface implementation, from MSC to BSC */
+
+/* (C) 2016 by sysmocom s.m.f.c GmbH <info@sysmocom.de>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/logging.h>
+
+#include <openbsc/debug.h>
+
+#include <openbsc/gsm_data.h>
+#include <openbsc/msc_ifaces.h>
+#include <openbsc/debug.h>
+
+int a_tx(struct msgb *msg)
+{
+	LOGP(DMSC, LOGL_ERROR, "message to be sent to BSC, but A-interface"
+	     " not implemented.\n%s\n", osmo_hexdump(msg->data, msg->len));
+	return -1;
+}
+
+int msc_gsm0808_tx_cipher_mode(struct gsm_subscriber_connection *conn, int cipher,
+			       const uint8_t *key, int len, int include_imeisv)
+{
+	/* TODO generalize for A- and Iu interfaces, don't name after 08.08 */
+	LOGP(DMSC, LOGL_ERROR, "gsm0808_cipher_mode(): message to be sent to"
+	     " BSC, but A interface not yet implemented.\n");
+	return -1;
+}