A subscriber station monitor system is provided for a subscriber station of a wireless telecommunications system. The subscriber station includes a transmitter/receiver for wireless communication with a central station and a communications controller for processing signals for transmission and/or received signals, a supply unit for connection to one or more telephone lines for user telecommunications equipment and a link connecting the communications controller to the supply unit, control data being passed in accordance with an internal protocol between the communications controller and the supply unit via the link. The station monitor system comprises a display and at least one user input device, a connector to the link and a protocol interpreter for extracting control data to be displayed on the display for monitoring the operation of the subscriber station and/or for inserting input control data to the link for configuring the subscriber station. By providing a separate monitor system for connection to the subscriber station in the link between the transmitter/receiver and the supply unit, monitoring and control of selected subscriber terminal functions is readily possible.