Abstract: A data handling system comprising a terminal (122) and a communications network (100), the terminal (122) being capable of communicating with the communications network (100), the network (100) comprising a host platform (124) for receiving an agent (30) associated with the terminal (122), the agent (130) being adapted to communicate, at the platform (124), with the at least one other agent.

Abstract: To estimate the response of a system to an input signal, on the one hand the input signal and on the other hand an observation signal, a component of which is said response to the input signal, are received, an error signal is determined by subtracting from the observation signal the input signal filtered by an identification filter representative of the response of said system, and the coefficients of the identification filter are adapted by taking into account the input signal and the error signal. If the adaptation takes into account an adaption stepsize .mu..sub.t, the latter is varied according to: .mu..sub.t =a/(c+d. P2.sub.t /P1.sub.t), where a, c and d denote positive constants, P1.sub.t denotes an estimate of the power of the input signal and P2.sub.t denotes an estimate of the power of the observation signal or of a disturbance component of said observation signal. The variable .mu..sub.t can also be employed to adapt the gains of an echo canceller with adaptive gains.