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Situation
Intercom Action
Ringing tone, which is terminated
before 10 rings are made (the count
of rings is variable)
Regarded as a successful call, continues for the
maximum timeout (maximum call duration). For details
refer to the text under the table.
Ringing tone, 10 rings are made (the
count of rings is variable)
Hangs up and dials the next number.
to
These digits are interpreted as password beginning.
Call extension or password beginning.
Hang-up command.
If the ringing tone stops before the predefined count of rings is achieved and the call
is thus very short (e.g. 2 seconds), it is not clear whether the call should be regarded
as successful. Therefore, a new type of automatic dialling has been added – type 4.
The difference is as follows:
Type 3 regards such a call as successful only if the door is opened.
Type 4 regards all such calls as successful.
Automatic Multiple Number Dialling with Confirmation
This mode is used where maximum connection reliability is required – for emergency
calls. The called line (the supervisory control centre, e.g.) must be operated by a well-
trained person to confirm connection. The DTMF is used as the most reliable criteria
for successful connection. The called line must press
on its telephone. If the called
number is busy or remains unanswered until the preset timeout or in other cases (see
the table), the intercom dials the next number in the sequence.
