Nippon Telegraph and Telephone Corp (NTT) yesterday announced that its regional fixed line operating divisions – NTT East Corp and NTT West Corp – intend to migrate all POTS/ISDN phone lines over to internet protocol (IP) equivalents by around 2025, Kyodo News reports. The switchover is the result of the inevitable demise of circuit switched networks and the corresponding rise in popularity of broadband and packet switched alternatives. NTT hopes to phase in the migration plan over a five year period starting around 2020, it said. NTT East and NTT West will notify existing customers of their plans concerning the migration and will carry out consultations with other telcos regarding interconnection of IP networks. Commenting on the Internal Affairs and Communications Ministry’s master plan to connect all Japanese households to fibre-optic networks by 2015, one NTT official said it would prove difficult to force people to switch by this date.