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M12 Vista: How to adjust the volume

How do I adjust the volume on the M12 Vista amplifier?


The M12 Vista has 2 volume adjustments. 

One for incoming (receive) sound and one for outgoing (transmit) sound.

For Incoming sound use the thumb wheel on the top of the base.

For Out going there is a panel next to where the batteries go.  remove that and there will be a 1-6 Configuration setting. To the right of the #6 setting, there is a blue box with a white dial in the middle.  Turn to the + to increase outgoing volume and towards the - will decrease it.




The 1-6 switch settings on the base are configuration settings. 

To view your configuration settings, remove the plastic cover on the left side of the amplifier.  You should see the numbers 1-6.  Different phone models require different configuration settings.  

Most phones will use setting #5 on the M12 Vista.

If you have any acoustic problems, try settings 1-6 to determine which works best for you. 

Here are some guidelines for configuration settings.

  • 1 = Carbons
  • 2 & 3 = Phone specifics, such as AT&T Merlin
  • 4 = Electret test setting
  • 5 = Electret w/batteries installed. (most phones)
  • 6 = Sirio (Spain)