Medias Mediatrix 1204, Справочное руководство

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Chapter 16 - Voice Transmissions User Gain
212 Mediatrix 1204
User Gain
The user gain allows you to modify the input and output sound level of the Mediatrix 1204.
You can compensate with the user gain if there is no available configuration for the country in which the
Mediatrix 1204 is located. Because the user gain is in dB, you can easily adjust the loss plan (e.g., if you need
an additional 1 dB for analog to digital, simply put 1 for user gain input).
X
To set user gain variables:
1. In the voiceIfMIB , locate the voiceIfTable group.
2. Define the following variables:
• voiceIfUserInputGainOffset : User input gain offset in dB (from analog to digital).
• voiceIfUserOutputGainOffset : User output gain offset in dB (from digital to analog).
Values range from -30 dB to +20 dB. However, going above +6 dB may introduce clipping/distortion
depending on the country selected. Under -24 dB, you will not have much signal either.
3. Restart the Mediatrix 1204 so that the changes may take effect.
Input Sound Level Limitations
Limitations in the Mediatrix 1204 analog to digital (input) gain may cause DTMF detection and voice quality
problems. There are two issues:
the default input gain for some countries is too high and you must lower it
the default input gain for some countries is properly set, but there is a maximum gain you must
not exceed
Default Input Gain too High
The default input gain for the countries listed in Table 137 is too high and you must lower it according to the
Required Offset value listed.
Caution:
Use these settings with great care. Mediatrix recommends not to modify the user gain variables
unless absolutely necessary because default calibrations may not be valid anymore.
Modifying user gains may cause problems with DTMF detection and voice quality – using a high user gain
may cause sound saturation (the sound is distorted). Furthermore, some fax tones may not be recognized
anymore. The user gains directly affect the fax communication quality and may even prevent a fax to be
sent.
In the Unit Manager Network Administration Manual , refer to chapter Ports Parameters , section Port
Configuration Window .
Table 137: Countries with Default Input Gain Too High
Country Default Input Gain Required Offset Resulting Gain
Australia +6.00 dB -1.04 dB +4.96 dB
Austria +6.00 dB -1.25 dB +4.75 dB
Brazil +6.00 dB -2.99 dB +3.01 dB
France +6.00 dB -1.25 dB +4.75 dB
Germany1 +6.00 dB -1.25 dB +4.75 dB
Italy +6.00 dB -1.25 dB +4.75 dB
Netherlands +6.00 dB -2.99 dB +3.01 dB
Spain +6.00 dB -1.25 dB +4.75 dB