diff --git a/tools/auto-enable.c b/tools/auto-enable.c
index 1d5b53bd..87fb0a8d 100644
--- a/tools/auto-enable.c
+++ b/tools/auto-enable.c
@@ -246,7 +246,7 @@ static void create_modem(DBusConnection *conn,
 	modem->conn = dbus_connection_ref(conn);
 
 	modem->sim_changed_watch = g_dbus_add_signal_watch(conn,
-				NULL, NULL, OFONO_SIM_INTERFACE,
+				OFONO_SERVICE, NULL, OFONO_SIM_INTERFACE,
 				"PropertyChanged", sim_changed, modem, NULL);
 
 	g_hash_table_replace(modem_list, modem->path, modem);
@@ -420,15 +420,15 @@ static void ofono_connect(DBusConnection *conn, void *user_data)
 	modem_list = g_hash_table_new_full(g_str_hash, g_str_equal,
 						NULL, destroy_modem);
 
-	modem_added_watch = g_dbus_add_signal_watch(conn, NULL, NULL,
-				OFONO_MANAGER_INTERFACE, "ModemAdded",
-						modem_added, NULL, NULL);
-	modem_removed_watch = g_dbus_add_signal_watch(conn, NULL, NULL,
-				OFONO_MANAGER_INTERFACE, "ModemRemoved",
-						modem_removed, NULL, NULL);
-	modem_changed_watch = g_dbus_add_signal_watch(conn, NULL, NULL,
-				OFONO_MODEM_INTERFACE, "PropertyChanged",
-						modem_changed, NULL, NULL);
+	modem_added_watch = g_dbus_add_signal_watch(conn, OFONO_SERVICE,
+				NULL, OFONO_MANAGER_INTERFACE, "ModemAdded",
+				modem_added, NULL, NULL);
+	modem_removed_watch = g_dbus_add_signal_watch(conn, OFONO_SERVICE,
+				NULL, OFONO_MANAGER_INTERFACE, "ModemRemoved",
+				modem_removed, NULL, NULL);
+	modem_changed_watch = g_dbus_add_signal_watch(conn, OFONO_SERVICE,
+				NULL, OFONO_MODEM_INTERFACE, "PropertyChanged",
+				modem_changed, NULL, NULL);
 
 	get_modems(conn);
 }
diff --git a/tools/huawei-audio.c b/tools/huawei-audio.c
index 8f3c5724..9997a581 100644
--- a/tools/huawei-audio.c
+++ b/tools/huawei-audio.c
@@ -514,17 +514,18 @@ static void create_modem(DBusConnection *conn,
 
 	modem->conn = conn;
 
-	modem->call_added_watch = g_dbus_add_signal_watch(conn, NULL,
+	modem->call_added_watch = g_dbus_add_signal_watch(conn, OFONO_SERVICE,
 				modem->path, OFONO_CALLMANAGER_INTERFACE,
 				"CallAdded", call_added, modem, NULL);
-	modem->call_removed_watch = g_dbus_add_signal_watch(conn, NULL,
-				modem->path, OFONO_CALLMANAGER_INTERFACE,
-				"CallRemoved", call_removed, modem, NULL);
-	modem->call_changed_watch = g_dbus_add_signal_watch(conn, NULL,
-				NULL, OFONO_CALL_INTERFACE,
+	modem->call_removed_watch = g_dbus_add_signal_watch(conn,
+				OFONO_SERVICE, modem->path,
+				OFONO_CALLMANAGER_INTERFACE, "CallRemoved",
+				call_removed, modem, NULL);
+	modem->call_changed_watch = g_dbus_add_signal_watch(conn,
+				OFONO_SERVICE, NULL, OFONO_CALL_INTERFACE,
 				"PropertyChanged", call_changed, modem, NULL);
-	modem->audio_changed_watch = g_dbus_add_signal_watch(conn, NULL,
-				NULL, OFONO_AUDIO_INTERFACE,
+	modem->audio_changed_watch = g_dbus_add_signal_watch(conn,
+				OFONO_SERVICE, NULL, OFONO_AUDIO_INTERFACE,
 				"PropertyChanged", audio_changed, modem, NULL);
 
 	g_hash_table_replace(modem_list, modem->path, modem);