METHOD OF AVOIDING NON-DESIRED INTERFERENCE BETWEEN SERVICES BY CREATING A TRUNCATED BINOMIAL TREE WHICH REPRESENT ACTIVE OR PASSIVE ACTION ELEMENTS

A method of avoiding undesirable interferences between services in a telecommunications system that includes basic software for a basic service and supplemental software for services supplemental to the basic service. The supplemental software is divided into action software which acts solely on the basic service, and supplemental software which acts on the remaining supplemental software. A supplemental service is represented by action elements. Combinations of action elements form nodes in a mathematical binomial tree. Only those combinations which correspond to interference, i.e., an undesirable behaviour, between supplemental services will form a number of structures, called interference event trees. Before a supplemental service can be executed, its action elements are compared with nodes in the interference event trees (55), with the intention of ascertaining whether or not the former coincide with action elements belonging to the nodes in the latter. Only those interference event nodes whose sets of action elements are equivalent with the set of action elements of the supplemental service or a set thereof are selected. An interference event node whose set of action elements is a subset of the action elements of a node that has already been chosen cannot be selected. Interaction software belonging to selected nodes in the interference event trees is added to the basic software.