Sony Ericsson Cordless DT590 - Manual (Page 21)

21 MD Evolution – Cordless DT590
Important
Network (submenu option)
The submenu option Network should only be used for
administration purposes by Ericsson service staff. Using this menu
option may cause a logout from the DECT/GAP network, and no
further calls will be possible.
Note : In case of a network unsubscription, the phone must
be logged on again by a service technician.