diff --git a/src/app.c b/src/app.c
index 6ab584d..6ec60ed 100644
--- a/src/app.c
+++ b/src/app.c
@@ -55,3 +55,20 @@ void app_setup(struct app_config *cfg)
 {
 	cfg->mncc.conn.on_disconnect = app_mncc_disconnected;
 }
+
+static void route_to_sip(struct call *call, const char *source, const char *dest)
+{
+	LOGP(DAPP, LOGL_ERROR, "Can not route call(%u) to SIP yet\n", call->id);
+	call_leg_release(call->initial);
+}
+
+void app_route_call(struct call *call, const char *source, const char *dest)
+{
+	if (call->initial->type == CALL_TYPE_MNCC)
+		route_to_sip(call, source, dest);
+	else {
+		LOGP(DAPP, LOGL_ERROR, "Can not route call(%u) to MNCC yet\n",
+			call->id);
+		call_leg_release(call->initial);
+	}
+}
diff --git a/src/app.h b/src/app.h
index 4e5b3fa..6bdc118 100644
--- a/src/app.h
+++ b/src/app.h
@@ -3,6 +3,8 @@
 #include "mncc.h"
 #include "sip.h"
 
+struct call;
+
 struct app_config {
 	struct {
 		const char *local_addr;
@@ -24,4 +26,6 @@ struct app_config {
 extern struct app_config g_app;
 
 void app_setup(struct app_config *cfg);
+void app_route_call(struct call *call, const char *source, const char *port);
+
 void app_mncc_disconnected(struct mncc_connection *conn);
diff --git a/src/mncc.c b/src/mncc.c
index fbbc88e..907384f 100644
--- a/src/mncc.c
+++ b/src/mncc.c
@@ -24,6 +24,8 @@
 #include "logging.h"
 #include "call.h"
 
+#include <osmocom/gsm/protocol/gsm_03_40.h>
+
 #include <osmocom/core/socket.h>
 #include <osmocom/core/utils.h>
 
@@ -33,6 +35,8 @@
 #include <errno.h>
 #include <unistd.h>
 
+extern void *tall_mncc_ctx;
+
 static void close_connection(struct mncc_connection *conn);
 
 static void cmd_timeout(void *data)
@@ -155,6 +159,21 @@ static void close_connection(struct mncc_connection *conn)
 		conn->on_disconnect(conn);
 }
 
+static void continue_call(struct mncc_call_leg *leg)
+{
+	char *dest, *source;
+
+	if (leg->called.type == GSM340_TYPE_INTERNATIONAL)
+		dest = talloc_asprintf(tall_mncc_ctx, "+%.32s", leg->called.number);
+	else
+		dest = talloc_asprintf(tall_mncc_ctx, "%.32s", leg->called.number);
+	source = talloc_asprintf(tall_mncc_ctx, "%.32s", leg->calling.number);
+
+	app_route_call(leg->base.call, source, dest);
+	talloc_free(source);
+	talloc_free(dest);
+}
+
 static void check_rtp_create(struct mncc_connection *conn, char *buf, int rc)
 {
 	struct gsm_mncc_rtp *rtp;
@@ -177,8 +196,19 @@ static void check_rtp_create(struct mncc_connection *conn, char *buf, int rc)
 	LOGP(DMNCC, LOGL_DEBUG,
 		"RTP set-up continuing with call with leg(%u)\n", leg->callref);	
 	stop_cmd_timer(leg, MNCC_RTP_CREATE);
-	mncc_send(leg->conn, MNCC_REJ_REQ, leg->callref);
-	call_leg_release(&leg->base);
+	continue_call(leg);
+}
+
+static int continue_setup(struct mncc_connection *conn, struct gsm_mncc *mncc)
+{
+	if (mncc->called.plan != GSM340_PLAN_ISDN) {
+		LOGP(DMNCC, LOGL_ERROR,
+			"leg(%u) has non(%d) ISDN dial plan. not supported.\n",
+			mncc->callref, mncc->called.plan);
+		return 0;
+	}
+
+	return 1;
 }
 
 static void check_setup(struct mncc_connection *conn, char *buf, int rc)
@@ -210,6 +240,11 @@ static void check_setup(struct mncc_connection *conn, char *buf, int rc)
 	}
 
 	/* TODO.. bearer caps and better audio handling */
+	if (!continue_setup(conn, data)) {
+		LOGP(DMNCC, LOGL_ERROR,
+			"MNCC screening parameters failed leg(%u)\n", data->callref);
+		return mncc_send(conn, MNCC_REJ_REQ, data->callref);
+	}
 
 	/* Create an RTP port and then allocate a call */
 	call = sip_call_mncc_create();