Abstract: A centralized test apparatus is provided for a telecommunications network which includes local switches and a core network. Each local switch is connected through terminating lines to terminal equipment such as telephone instruments. The test apparatus enables a field engineer to record routing data in a centralized database. When a field engineer connects a telephone instrument to a terminating line in a node in an access network, the engineer can dial the number of the test apparatus. The test apparatus retrieves the calling line identity on answering the call. It then invites the field engineer to enter an identifier for the type of node, the number of the node and the number of a terminal inside the node through which the terminating line passes. The calling line identity, the type of node, the number of the node and the number of the terminal are then used to update routing data in the database. Thus is provided a method of updating and maintaining routing data.