In order to adjust the sidetone levels locally on a Eclipse version ICS-2003E panel the user must follow the these steps:
1.  Connect a headset to the ICS-2003 panel and verify that the panel has auto-sensed the headset and disabled the speaker and gooseneck mic
2.  Activate a talk key on the ICS-2003 panel.
3.  Press the Menu button on the panel's keypad to activate the menus.
4.  Press the lever key for "Local Configuration"
5.  Press the lever key for "Internal Level Adjust"
6.  Panel Mic, Headset Mic and Sidetone level bars will be displayed, press the lever key upwards or downwards to adjust the sidetone for the headset mic until a comfortable level is achieved.  
7.  Once this completed exit the menu by pressing the lever key under "EXIT" downwards three times to exit all the panel's menus. 
Note:  If a headset isn't plugged into the panel or if a talk key isn't selected then the sidetone level bar cannot be adjusted by it's associated lever key.