Portable telephone equipment

After recovery from a power failure in a main power source (2), if it is a short break, recovery time is obtained from a built-in clock (6) and the period of the short break is calculated from this recovery time and the time when the short break occured. If the period of the short break falls within a resumption allowable time range, a resuming function is effected by setting information on the pre-break operation state of the equipment prestored in a memory (7) so that the equipment can continue operation.