Set Custom Time Zone on Remote Edge 9800 series Phones

Determine the correct time zone for the phone (use a GMT offset chart like this one).
Modify this file: PHONE1_custom.xml with the correct GMT code. Download the sample file and open it in Notepad.
For areas that do not use Daylight Savings Time, be sure to disable it by including the command to disable (see PHONE_custom.xml for a pre-built file):
<DST>
<Active>disable</Active>
</DST>
Save the file (see Custom Configuration Files for Edge IP 9800 Series Phone).
NOTE: The file should not be saved to the Wave as PHONE1_custom.xml. The Custom Configuration article specifies how to correctly name the file.
Trigger Wave to recognize the changed files. This can be done in one of two ways:
1. Restart Wave. This will take the system out of service, but is the simplest way if a large number of custom files were edited.
2. When needing to just adjust a single phone or during operating hours, make a change to the user's settings in Global Admin (see Login to User/Group Management). This will cause Wave to update settings including integrating the custom changes.