Interface for digital telecommunications system

This invention relates to a method of creating an interface between a node and a local exchange of a digital telecommunications system, and to apparatus for preparing instructions for the creation of such an interface. The invention is particularly applicable to the creation of a V5.2 interface between an Access Node (AN) and a local exchange of an SDH telecommunications system. A node () and a local exchange () communicate with each other over a V5.2 interface created in response to instructions prepared by a computer (). The method of preparing the instructions involves the steps of allocating identification data to the signal means linking the node and the local exchange so as to enable the latter to determine the identity of the node communicating over the signal link, specifying which C channels are to be transmitted along the signal link means, and, for each specified channel, specifying the C paths, i.e. the type of telecommunications traffic, to be carried thereby.