This interface allows clients to receive network time and timezone updates broadcast by mobile networks. The timezone data provided by the network. It may include one of more of the following fields: 'offset': offset of the timezone from UTC, in minutes (including DST, if applicable). 'dst_offset': amount of 'offset' that is due to DST, in minutes. 'leap_seconds': number of leap seconds included in the network time. Gets the current network time. This method will only work if the modem tracks, or can request, the current network time; it will not attempt to use previously-received network time updates on the host to guess the current network time. If the network time is known, a string containing a date and time in ISO 8601 format. If the network time is unknown, the empty string. Sent when the network time is updated. If the network time is known, a string containing a date and time in ISO 8601 format. If the network time is unknown, the empty string.