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Due Fili Plus telephone interface
5.16 Telephone line tones (888 83 T F1 F2 D)
The interface automatically recognises the interruption of a telephone communication or when the telephone number
called is busy based on the tones present in the line and the configuration of the telephone line parameters is used to
define the frequencies of the line tones envisaged in the various international standards and their minimum duration.
For instance, in Europe line tones envisage a frequency of 425Hz whereas in the United States of America, they
consist of a 480Hz tone and a 620Hz tone.
The definition of the minimum duration (T) of the tones and the maximum difference (D) between the duration of the
tone and the pause that make up the busy signal is necessary for cases of lines with interference or in the presence
of echoes; generally, the more interference there is on the line, the longer the minimum recognition duration.
To define the parameters of the telephone line, proceed as follows:
• Call the internal tap-off or the telephone number where the interface is connected on a telephone, wait for the
call tone and the subsequent brief tones (three repeated brief tones)
• T
ype in code
888
• Type in programming code
83
• Type in the code corresponding to the minimum time:
0 = 40ms
1 = 80ms
2 = 120ms
3 = 160ms
4 = 200ms
5 = 240ms
• Type in the code corresponding to the minimum frequency:
0 = 300Hz
1 = 325Hz
2 = 350Hz
3 = 375Hz
4 = 400Hz
5 = 425Hz
6 = 450Hz
7 = 475Hz
8 = 500Hz
9 = 600Hz
• Type in the code corresponding to the maximum frequency:
0 = 325Hz
1 = 350Hz
2 = 375Hz
3 = 400Hz
4 = 425Hz
5 = 450Hz
6 = 475Hz
7 = 500Hz
8 = 525Hz
9 = 700Hz
• Type in the code corresponding to the maximum difference recognised between the tone duration and the
pause duration:
0 = 200ms
1 = 320ms
2 = 400ms
3 = 520ms
4 = 600ms
5 = 720ms
6 = 800ms
7 = 920ms
8 = 1000ms
9 = 1120ms
