Adjust sidetone volume as follows:
6.5 Ground Checks (Configuration Mode)
The following checks are performed in configuration mode. To enter configuration mode, remove power from the GTR/GNC. With the GTR/GNC turned off, press and hold the ENT key and apply power to the GTR/GNC by turning the COM volume knob clockwise. Release the ENT key when the display activates and ?Garmin? appears on the screen.
The first page displayed is the Config Mode page. While in configuration mode, pages can be selected by turning the outer knob to select the high-level page, turning the inner knob to select the subpage, and then
pressing the ENT key to select the desired page. There are five main page headings: SYS, NAV, COM, AUD, and LOG. From the main heading, turn the inner knob to select the desired subpage and then press the ENT key. See Figure 6-1.
6.4.4.1 COM Sidetone
The COM Sidetone page (Figure 6-18) allows the installer to adjust the COM sidetone volume. COM sidetone is the audio spoken into the COM microphone. This setting only affects the volume of the sidetone for the GTR/GNC COM during PTT. To adjust the COM sidetone volume, rotate the smaller inner knob to the desired value. This field is adjustable in the range of 0 (zero) to 100. The default is 50.