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Dear all,

I am testing an inband DTMF detection algorithm at the
moment.Since I am new in the area, I'd appreciate some
clarification on some of the specifications in ITU-T
recommendation Q.24.

1. Maximum Non-operation signal duration: I understand
that the recommendation requires the detector not to
respond to any signal whose duration is shorter than
this number. However, what should I do with signal of
duration between this maximum non-operation duration
and the minimum operation duration?
The same also apply to the gap between the maximum
non-operation and the operation signal power levels
per frequency.

2. For inband DTMF, the signal is not subject to (or
at least is much less subject to) channel distortion
and suppression. In light of this, are the tests on
different signal power levels and imbalance between
different frequencies still relevant?

Thanks for your response in advance.

Jiaquan

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