A telephone exchange (1) arranged to communicate with communication units (2, 3, 4, 5, 7) and to provide a plurality of electronic call assistants to the communication units, a first electronic call assistant (12) being provided to a first communication unit (2) and a second electronic call assistant (14) to a second communication unit (4), the first electronic call assistant (12) having access to a distinct first database (36), the second electronic call assistant (14) having access to a distinct second database (38), wherein the first (12) and second (14) electronic call assistants share a common database (40).