A data processing system is dedicated to one or more calling users, and comprises (i) storage means (Mi), suited for storing information data indicative of one or more communication addresses of communication terminals (Ci,Ti,FTi) used by the calling user (Ui), and an accessibility status of such calling user through each one of said terminals (Ci,Ti,FTi), (ii) interfacing means (Ii), allowing the calling user (Ui) to request the setting-up of a communication with at least one called user (Uj), and (iii) management means (Gi) capable of negotiating with another data processing system (Dj), dedicated to the called user (Uj), and according to at least the information data stored in their respective memorization means (Mi, Mj), the set-up of the communication, requested by the calling user (Ui) between two terminals likely to be respectively accessed by the calling user (Ui) and the called user (Uj).