2N Lift emergency phone 2N LiftNet - Manual, 1446 v1.8.3 - Manual (Page 78)

Function Description (for Advanced Users) 4.4
78
Automatic Dialling of Multiple Numbers with
Confirmation
Up to 6 telephone numbers including repetitions can be stored for dispatching office
calling. LN then tries to call all the numbers stored. To confirm successful calls, LN
uses tone dialling (DTMF). Having received a call manually, the dispatching office
officer has to press the
button on his or her telephone (tone dialling). If the
called line is busy, or is unanswered within a timeout, or the call is not confirmed, LN
dials the numbers in the sequence until it exhausts all pre-set attempts. The
procedure is the same for checking calls or failure reports but a separate group of six
numbers can be used.
Evaluation of Situations during Automatic Audible Dialling with
Confirmation
Situation LN Activity
Busy tone after number
dialling end LN hangs up and dials the next number in the
sequence.
Call or silence
LN waits for a pre-set period of time (see Parameter
913).
Ringing tone
LN waits for a pre-set count of rings (see Parameter
954), then hangs up and dials the next number.
Continuous tone (on a PBX
line, e.g.)
LN hangs up and dials the next number.
DTMF character , or LN hangs up immediately and dials the next number.
DTMF character
LN confirms receipt (2 beeps), mutes the current voice
message and the call goes on for the maximum pre-set
time (maximum call duration).
These digits are interpreted as control characters
(refer to Subs. 3.6).
Note
 The PSTN connection quality is not so high as to identify the above
mentioned situations reliably in all cases. Moreover, excessive noise in the
lift cabin may decelerate automatic dialling (due to inability to recognise
the busy tone, e.g.). In general, DTMF is the most reliable type of
signalling and so is used for confirming receipts. Thus, the connection is
established (yet for a shorter time than usual) even in extreme cases, e.g.
when LN cannot identify the DTMF.