PURPOSE: To estimate the accurate power consumption and to inform a user of the remaining duration of a call by providing an algorithm selector and a selection information holding circuit and transmitting the held signal to a control circuit which calculates the power consumption of a CPU, etc.

CONSTITUTION: When the error signal calculated by an error signal calculator 38 has the value larger than a certain level, an algorithm selector 41 decides that a transmission line has an extensive fluctuation and the updating of an LMS is impossible and then produces a switching signal to switch the updating algorithm to an RLS. The tap coefficient updating devices 34 and 35 switch the updating algorithms. When the error signal of the LMS has the value smaller than a fixed level, another error signal used for no equalizing operation is obtained. If the value of this error signal is smaller than a fixed level, the equalizing operation is not carried out. Meanwhile the circuit 42 holds its selected for a 1-shot period and then transmits this signal to an external circuit like a control circuit of a CPU, etc., from an equalizer 43. Thus the control circuit calculates the power consumption.