![background image](http://html1.mh-extra.com/html/nec/dterm-dtz-8r-1/dterm-dtz-8r-1_quick-start-manual_3873364002.webp)
When you see Service Menu in the display of the DTZ-8R-1, press the Down arrow until you see Audio
Gain Offset
When you see the arrow to the left of Audio Gain Offset, press the Select button
Service Menu
>HS Version
BU Version
Clear Setting
Audio Equalizer
Speed Dial
Service Menu
Speed Dial
Wordwrap
F8 Select
Quick Dial
>Audio Gain Offset