diff --git a/src/libmsc/ussd.c b/src/libmsc/ussd.c
new file mode 100644
index 0000000..72f26bd
--- /dev/null
+++ b/src/libmsc/ussd.c
@@ -0,0 +1,79 @@
+/* Network-specific handling of mobile-originated USSDs. */
+
+/* (C) 2008-2009 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2008, 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2009 by Mike Haben <michael.haben@btinternet.com>
+ *
+ * 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/>.
+ *
+ */
+
+/* This module defines the network-specific handling of mobile-originated
+   USSD messages. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <openbsc/gsm_04_80.h>
+#include <openbsc/gsm_subscriber.h>
+#include <openbsc/debug.h>
+#include <openbsc/osmo_msc.h>
+
+/* Declarations of USSD strings to be recognised */
+const char USSD_TEXT_OWN_NUMBER[] = "*#100#";
+
+/* Forward declarations of network-specific handler functions */
+static int send_own_number(struct gsm_subscriber_connection *conn, const struct msgb *msg, const struct ussd_request *req);
+
+
+/* Entrypoint - handler function common to all mobile-originated USSDs */
+int handle_rcv_ussd(struct gsm_subscriber_connection *conn, struct msgb *msg)
+{
+	int rc;
+	struct ussd_request req;
+	struct gsm48_hdr *gh;
+
+	memset(&req, 0, sizeof(req));
+	gh = msgb_l3(msg);
+	rc = gsm0480_decode_ussd_request(gh, msgb_l3len(msg), &req);
+	if (req.text[0] == 0xFF)  /* Release-Complete */
+		return 0;
+
+	if (strstr(USSD_TEXT_OWN_NUMBER, req.text) != NULL) {
+		DEBUGP(DMM, "USSD: Own number requested\n");
+		rc = send_own_number(conn, msg, &req);
+	} else {
+		DEBUGP(DMM, "Unhandled USSD %s\n", req.text);
+		rc = gsm0480_send_ussd_reject(conn, msg, &req);
+	}
+
+	/* check if we can release it */
+	msc_release_connection(conn);
+	return rc;
+}
+
+/* A network-specific handler function */
+static int send_own_number(struct gsm_subscriber_connection *conn, const struct msgb *msg, const struct ussd_request *req)
+{
+	char *own_number = conn->subscr->extension;
+	char response_string[GSM_EXTENSION_LENGTH + 20];
+
+	/* Need trailing CR as EOT character */
+	snprintf(response_string, sizeof(response_string), "Your extension is %s\r", own_number);
+	return gsm0480_send_ussd_response(conn, msg, response_string, req);
+}