Abstract: System X telecommunications system has a private circuit employing a switched connection, the circuit connecting from an originating subscriber to a terminating subscriber via an original directory number, and is controlled so that when the connection is terminated, an attempt is made to re-establish the connection from the originating subscriber by use of an alternative directory number where an indication is received that a further call may be successful, the attempt to re-establish the connection is repeated using the original and alternative directory numbers alternately until the call is re-established.