3Com MSR 50, MSR 30 manual Echo-canceller, 2591

2591

Table 682 Meaning of the index numbers

Index Meaning Value range Remarks

10The frequency of the first extra frequency point specified for detection.

In addition, it must be a frequency 100 Hz greater than or less than the row and column frequency groups.

300 to 3,400 Hz, - with a default of 300 Hz.

11The frequency of the second extra frequency point specified for detection.

In addition, it must be a frequency 100 Hz greater than or less than the row and column frequency groups.

300 to 3,400 Hz, - with a default of 3,200 Hz.

12The lower limit of the amplitude of the input signal. The average amplitude must be greater than this threshold for the input signal to be recognized as a DTMF digit.

0 to 700, with a default of 375.

The larger the value is, the higher the detection reliability is. However, the sensitivity drops.

Description Use the dtmf threshold command to configure the sensitivity of DTMF digit detection.

Use the undo dtmf threshold command to restore the default.

The dtmf threshold command issues the thresholds for DTMF dial tone detection to the underlying layer DSP for the purpose of tuning detection sensitivity and reliability of the device subtly. Inside the DSP, a set of generic default values have been configured. They are 1,400, 458, -9, -9, -9, -9, -3, -12, -12, 30, 300, 3,200, 375, with their index being 0 through 12. Professionals can use this command to adjust the device when DTMF digit detection fails. In normal cases, the defaults are adopted.

Example # Set DTMF threshold 9 in voice subscriber line 1/0.

<Sysname> system-view [Sysname] voice-setup [Sysname-voice] subscriber-line 1/0

[Sysname-voice-line1/0] dtmf threshold analog 9 40

echo-canceller

Syntax echo-canceller { enable tail-length milliseconds }

undo echo-canceller { enable tail-length }

View FXS/FXO/E&M voice subscriber line view

Parameter enable: Enables the echo cancellation (EC) function.