you can adjust the mic sensitivity at the phone with this procedure (FB3 is the third button up from the bottom in the row on right side)

1. Press 3+6+9+Hold (simultaneously).
2. Press 0.
3. Press Feature Button 3 (FB3) to toggle On/Off.
FB3, LED On: Lower sensitivity
FB3, LED Off: Normal sensitivity
4. Press Hold to set the option.
5. Go off-hook, then on-hook to exit the program mode.


PBX Battery backup systems

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