Call waiting with “Caller ID” uses a special signal in
order to warn you about an incoming call, during another call there are shown the
name and number of the calling subscriber on the display. The function also
allows switching between two calls.
Rates of the call shop are usually defined by the administrator, but the rate plans are managed in the main database of the billing system. All the rates are dependent on the charging policy; in case of a destination based billing rates are specified according to the area codes in the supported destinations.