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NTEGRATED
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IRCUITS
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M-980-02
click and “hello” at the far end). Some applications will
require special methods like speech detection, but
most can be reliably handled with the M-980-02 and
simple cadence measurement.
As can be seen, the tones used for the same
purposes in different systems may not be the same.
Standards do exist and should be consulted for your
particular application. In North America, AT&T’s
“Notes on the Network” or EIA’s RS-464 PBX
standard, should be reviewed. In Europe, tone plans
may vary with locale, in which case the CEPT
administration in each country must be consulted.
Outside these areas, national PTT organizations can
provide information on the systems within their
borders.
Device Timing
Note: Application or removal of high level signals outside the must-detect range may cause momentary detection, which may be filtered by time
guarding the output.
Call Progress Tones
Time Value Significance
t
MD
40ms
A valid tone will always be detected if it is at least 40ms long.
t
ID
40ms @ -38dBm
Inter-tone gaps must be detected if greater than this duration.
85ms @ -10dBm
t
B
18ms
Drop-outs of valid tone of up to 18ms will be ignored.
Frequency 1 Frequency 2 On / Off Use
350 +440 Continuous
Dial Tones
425 - -
-
600 X 120 -
-
400 - -
-
480 +620 0.5 / 0.5s
Line Busy Tones
600 X 120 -
-
480 +620 0.25 / 0.25s
Reorder Tones
600 X 120 -
-
440 +480 2.0 / 4.0s
Audible Ringing
500 X 40 -
-
440 - 0.5s burst
Var ious
