Patent ID: 11950319
Assignee: NTT DOCOMO, INC.
Field: Computer technology (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 2:
3. A method for erasing data on a user that remains in an after-use terminal device due to change of terminal devices in a communication system including a host device and two or more terminal devices,
the host device including:
a host memory to store terminal identification data respectively unique to the two or more terminal devices and identification data respectively unique to two or more users; and
a processor configured to:
a) examine presence or absence of data in the host memory; and
b) perform control to broadcast data to all the two or more terminal devices,

each of the two or more terminal devices including:
a terminal memory to store data on a user and own terminal identification data; and
a processor configured to erase data stored in the own terminal memory,

the method comprising:
examining, responsive to newly storing in the host memory user identification data UI of a certain user among the two or more users and terminal identification data TI of one terminal device that is used by the certain user and is among the two or more terminal devices, presence or absence of at least another terminal identification data TI-p that corresponds to the user identification data UI, excluding the terminal identification data TI and one or more other terminal identification data respectively corresponding to one or more, being currently used by the certain user, among the two or more terminal devices;
performing, responsive to presence of the at least another terminal identification data TI-p control to broadcast predetermined instruction data together with the terminal identification data TI-p to all the two or more terminal devices; and
erasing, responsive to match of the own terminal identification data and the at least another terminal identification data TI-p received together with the instruction data from the host device, the data on the user stored in the own terminal memory.